Although the odds of winning a big lottery prize are always low, for some people who bought scratch-off lottery tickets in California, the odds of winning might be even lower: none at all.

Since 1996, California has sold millions of dollars worth of scratch-off tickets even after the top prizes offered — up to $100,000 — were already won. The tickets are the state lottery's most popular product.

State lottery officials, who admitted the practice last summer, have said that state agencies are exempt from false-advertising laws.

At least one purchaser — Amy Stanley of San Francisco — was unsatisfied with the explanation and filed a lawsuit that will go to trial next month. Stanley says she bought tickets worth $1, $2, and $3 each expecting to have a chance of winning prizes that were already claimed.

"No one has a clue," Stanley's attorney Kevin Roddy stated.

Since the suit was filed, California has placed a disclaimer on its tickets saying that "some prizes, including top prizes, may have been claimed." Roddy wants California to do more, and plans to argue that the state should follow in the footsteps of Massachusetts.

"In Massachusetts, when the Lottery Commission learns the top prizes are claimed, it immediately sends an electronic message to its retailers, and that's posted. People know what they're getting," Roddy said.

Although Roddy might not be satisfied by the disclaimers, one gambling watchdog group thought they were a step in the right direction.

"I think it's great. They're saying you bought a ticket that may be worthless," said Cheryl Schmit of Sacramento-based Stand Up for California.

The Associated Press contributed to this report.