STATELINE -- "Advantage" gamblers, skilled bettors who are often ousted from Nevada resorts if spotted at blackjack tables, were welcomed Tuesday at an international conference on gambling -- held at a Lake Tahoe casino.

One of them, James Grosjean, didn't take any chances on getting tossed by hotel security guards. He showed up in disguise at the 13th International Conference on Gambling & Risk-Taking, wearing a long black wig. He also sported sun glasses and a blacked-out front tooth.

As the conference opened, Grosjean and fellow "advantage" gambler John Chang were among speakers who covered topics ranging from legal ways to beat the odds to problem gambling, efforts to lessen smoking in casinos, online poker players and sports betting.

Officials at Harrah's Lake Tahoe, the resort where the weeklong event is being held, weren't worried about the presence of Grosjean, Chang and several other gamblers whose skills at counting cards and taking advantage of sloppy dealers can give them an edge over the mathematical advantage that a casino has in blackjack and other games of chance.

"No, there's no real cause for alarm," said Harrah's spokesman John Packer. "We know who they are."

Chang, part of a group of MIT students who in the early 1990s formed a team of expert card counters who reportedly made millions of dollars at blackjack tables, detailed the methodical approach the group used to avoid scrutiny, account for wins and losses, train new players and preserve team loyalty.

Those steps, beyond learning how to keep track of cards played in blackjack to improve odds of a winning hand, are critical, said Chang.

Card-counters can turn the 1 to 2 percent advantage that casinos have to a 1 to 2 percent advantage for themselves -- but Grosjean said a gambler's advantage can increase to more than 6 percent for "hole-carders" like himself, who try to spot the blackjack dealer's concealed hole card.

Both Chang and Grosjean also complained about being roughed up, handcuffed and hassled by casino security over the years.

Grosjean currently has a case before the Nevada Supreme Court stemming from a confrontation with guards at a Las Vegas club.

Chang said there are so few highly successful "advantage" gamblers that the efforts by casino managers to keep them off their properties are "laughable."