Now imagine that the brash player is the American Gaming Association, backed by another powerful player, the Culinary Union. The silent player, of course, is the Internal Revenue Service, ever strategizing without disclosing.

Last week the AGA made lots of noise about the IRS sending out audit notices to more than 1,000 Las Vegas hospitality workers. Some workers who already paid taxes under the tip program were shocked to learn that they owed an additional $1,000 or more in back taxes.

The Culinary accused the IRS of double-crossing workers who signed up for the IRS' tip program — a negotiated agreement under which participating Nevada casino workers report a fixed rate of tips per hour on their tax returns. As a condition of participating in the program, workers can't be audited, the Culinary and the AGA say.

"If someone volunteers for the program, leave them alone," AGA Vice President Wally Chalmers said. "The IRS heard that loud and clear. Their actions have put the program in jeopardy. If these audits continue there's going to be a massive withdrawal from the tip program."

The tip agreement, which dates from the early 1990s, has been tweaked several times over the past several years. The result is much like a union contract — a politically charged and delicate compromise subject to the whims and demands of both parties. The casino industry has successfully fought off IRS pressure over many years to increase the tip estimates workers pay. While the IRS says the estimates are way too low, the industry says IRS proposals to increase reported tips twofold and even threefold are out of line and unfair. Expect both parties to make these claims as long as casinos are in Nevada.

The latest agreement expires at the end of this year. Casino executives and their lobbyists met last month to negotiate a renewed agreement and are expected to resume those discussions this month. The audits of Nevada casino workers, which picked up several months ago, provide lots of ammunition against the IRS at a critical point in the negotiating process. You might say that the gaming faction, in this case, has a chip lead on its opponent.

The IRS, no slouch in the negotiation game, will no doubt be asking for an increase in the tip estimates based on factors such as Las Vegas' booming economy and a boost in luxury business from high-end travelers — people who tend to tip more.

Nevada will use its political muscle, particularly heavy hitters Sens. Harry Reid and John Ensign, to bolster its position.

The IRS won't comment on the audits, leaving the industry to blame the IRS for relying on faulty information.

This is where the flow of information starts to get spotty.

Workers under the tip agreement report a fixed rate of tips per hour on their tax returns. The rate varies according to casino and shift with the idea that swing shift servers at luxury resorts would obviously pay more than day shift servers at, say, midpriced hotels.

In an interview I conducted with the IRS last year, a representative disclosed that each hotel supplies detailed information on the work history of each tipped employee at the end of the calendar year. The list includes the hours each employee worked in a particular position, accounting for job and shift changes. When workers turn in their tax returns for that year, the IRS compares figures from the workers' W-2 forms with their work history information supplied by the hotels. The IRS says it typically issues an audit notice — requesting clarification or payment — if the numbers don't match.

• Is the IRS second-guessing tipped workers? Is the IRS relying on real-time tip histories and trying to match that with tip "estimates?" If so, mismatches, and audit letters, are likely.

• Some of the workers who were audited appear to have a complex work history — they are workers who changed jobs or shifts midstream, which would have affected their tips. Is the IRS aware of these changes? If not, they could be comparing tip estimates provided by the hotels with an expected estimate that doesn't reflect reality.

While there's evidence that workers have unfairly been audited, the IRS may have more latitude to audit than anyone has let on. The IRS' 16-page revenue procedure on the gaming tip agreement from 2003 — the latest three-year agreement that is now up for negotiation — clearly states that workers are required to report tips that are "at or above" the estimates in the tip agreement. W-2 tips that come up short are subject to audit unless the worker can "substantiate" the decrease with documentation.

Could reporting or accounting errors have opened up a gaping loophole big enough to capture unwitting, taxpaying workers along with the freeloaders?

• In 2003, the IRS expanded the casino tip program nationwide — praising the program as a win-win situation for workers, casinos and the tax agency. If casinos in other states are participating in the program, as well they might, why have there been no complaints about massive audits of casino workers elsewhere?

Something is rotten in the state of Nevada. And the IRS, which isn't talking, has a lot of explaining to do.

Chalmers said Nevada casinos say they have a simple solution.

"We told them, ‘If you're not content with our collection, come in and do whatever sampling you need to do. Come in and certify our data collection — it shouldn't be that hard,'" Chalmers said.

The IRS will be entering negotiations with a big chip stack of its own.

The agency has long maintained that tip workers in cash businesses — especially Nevada's casino workers — are most likely to underreport their tips. The IRS negotiated Nevada's tip agreement as a way to collect tips that the agency believed would otherwise go unreported. Like a casino's poker rake, it's guaranteed money that approaches $900 million per year. IRS tip agreements struck with food and beverage businesses nationwide generated at least $18 billion in tip taxes as of 2003.

Tax attorneys who have battled the IRS still acknowledge that workers are getting the better deal: workers generally earn more tips on average than the amount they are required to report under the agreement, they say.

The agreements make life easier for the IRS, saving much-needed time and money on audits and investigations. They make life a whole lot easier for workers, who might otherwise have to do the unthinkable and keep their own books.

This game of poker will soon come to another hard-won conclusion. And when it does, the winner will agree to split part of the winnings with its opponent. The question is how much the winner will keep.