Well I'm going to be a bit silly here but I've never had much use for gaydar.
Thusly I shall be the first to admit that one could fool me easily enough.
Why on earth would I need gaydar? I am a heterosexual female and so far as my past recalls, I've never had any sort of relationship, sexual or otherwise, with a homosexual. Further, homosexuals have never ever "hit" on me in any fashion.
I'm pretty sure that most of the guys on my fave home decorating shows are homosexuals and I consult for a beauty salon and a couple of those operators were plainly gay, even I could see that.
Frankly, it's my HUSBAND who spots a gay guy a mile away and usually he points it out to ME. Heh.
I'm gonna ask him about Ken Mehlman. He never mentioned a gay possibility there.