The last time I stayed there (Sept 02) Flamingo was OK with security.  I don't recall security at elevators at night, but I wasn't looking too hard.  There were many girls working the bar at the end of the casino farthest from the lobby early in the evening.  They were, for the most part, older than what you might expect (in their 30s and one Asian woman probably in her mid-40s).

Late night (after 1AM) there were a bunch of girls hanging around the bar closest to the lobby.  They looked very young.  A few were playing the cheap slots, and one of them, one night, jackpotted a slot for a few hundred, and announced that she didn't have to work that night, so she went home.  She was back the next evening.

I stay in LV Sun-Thurs when I go, so I can't tell you anything about the week-ends.