Lots of people occupied casinos, but it's harder to tell how many were turned off by them. During my brief stay in SL, I made an ill-fated attempt to fly around the grid, looking for places that had large numbers of people in the hopes of finding something interesting. More often than not, said places turned out to be casinos, with large numbers of paid AFK campers (by paid we mean fractions of pennies per hour) to boost the search rankings. (This also meant that the search rankings were worthless, since they would always yield casinos.)