I'm not concerned about how often it happens. I'm concerned about the potential for it to happen. The Richard's example shows that potential. Your insistence on more examples as some metric of proof is none of my concern.

There are enough examples of men being ruined by female accusations. Most recent I remember from HN is the GitHub founder being fired. Then there was the guy who reverted the gendering comments on some open source project (was it NodeJS?) and received a shit storm. Another one I remember is the Ruby conference where an employee flirted with her boss at a restaurant (letting her colleagues drink from her navel) and then called rape when he ended up slow-dancing with her. Adria Richards is also a good example - why wasn't she expelled from the conference, what good is a policy if it isn't being enforced?

Your question is of course also absurd because you ask for examples of the absence of something. It doesn't create much publicy if somebody decides to skip a conference. I personally would think twice about going to a conference with such policies because I consider them insulting.

Another victim could be women - if the safe way to attend a conference is not to talk to women. I remember a post on HN by a woman who has long been a coder/hacker and got along very well with the male coders. But recently she noticed that they don't dare to invite her (or was it just the newcomer women whom they didn't know so well yet) to parties and after show events anymore for fear of unwarranted accusations.

No. I simply refuse to adopt his/your standard of proof. If that makes you think you've won the argument then so be it.