I don't think it's more common at geek conferences than at dance clubs.
BUT, I would expect it to be about the same level (and possibly higher) at the 'private parties' near the geek conferences.
You have an environment very similar to the dance clubs, but without bouncers to keep people in line (if only by intimidation)
In addition, the fact that the 'private parties' have a much smaller female population means that the odds of any particular female being abused is probably significantly higher since there are fewer targets for the misbehaving guys to go after.
Even if the absolute number of problems at these 'private parties' is 1/4 that of the dance clubs, the fact that there are generally fewer than 1/10 as many females would result in each female being affected by an problem 2.5 times as frequently.