In the fashion world there are a few photographers which almost openly do this, known to us mostly because they got so used to it they put their dick in a girls mouth unannounced and rather than suck it she talked to the press about it. [1]
An old colleague worked at an IT company thirty years or so ago and on the upper management floor, as he described it, the secretaries were all paid $200k/yr and up to be, essentially, professional hookers.
It is almost certainly a problem in some circles in the tech investors industry as well.
This is just a, very welcome, statement to tell investors that if they want to be such an investor they'll be locked out of YC forever and to tell founders that they can expect to be backed up when they report this.
[1] http://jezebel.com/i-felt-a-dick-pressing-into-my-face-terry...