In July, Lynn Evenchik paid more than $300 for a weeklong car rental at Avis.In a just-filed federal class-action lawsuit, Evenchik's lawyers contend she was denied discounts of up to 20 percent that Avis "made available to gay and lesbian renters" through two different groups: a gay business association and a gay travel group.California Western School of Law professor Ari Waldman said, "She's arguing [that] because she's not gay she can't access the discount. As such, she's claiming discrimination on the grounds of sexual orientation."Waldman said Evenchik is claiming the discounts violated state anti-discrimination laws.Experts said one fact could put the brakes on her case."Anybody can join our organization. Our surveys show more than a quarter of our members are straight," said Tom Luhnow, who heads the Greater San Diego Business Association, a local gay business group.Luhnow said his group and two others mentioned in the suit welcome everyone and have plenty of straight members.Waldman said that fact hits at the core of Evenchik's argument."The discrimination here -- if it exists -- is on the basis of membership in an organization which she is free to join tomorrow and was free to join yesterday," Waldman said.Yet, there are no indications Evenchik has joined, which has led some to question her motives."There are people out there who are hateful and have an agenda. I hope she doesn't have an axe to grind, but you never know," said Luhnow.Avis declined to comment on the lawsuit.10News was able to contact Evenchik, who owns a travel agency in the Tucson, Ariz., area. However, she and her attorney declined to comment on the matter.