I would guess. Makes a 10-20 game easy. Both the Mirage and Bellagio had (have?) $10 and $20 chips, which are used for that purpose. Both have sizable poker rooms. In Aruba, both the Excelsior and the Radisson (the two which have had poker the longest and most consistently) have both had $20 chips used in their poker rooms.

Just a guess as to California, though.

Michael Siskin