No truth in labeling? What do you mean? I think my gaydar is pretty good, if I do say so myself. There's been several men I've seen in public, complete strangers but I've felt something, saw something. They're often with their girlfriends or wives, too but I see how they're looking at me. Some look very uncomfortable and will look away from me, while others will look as discreetly as possible.
I'm familiar with all of that because I used to do the same thing, only I was about eleven or so. I am still not in an area where a man can openly flirt with another man. I'm a flirtatious guy but if a gay man hit on other men in this area, he would get hit and I refuse to risk damage to my perfectly high cheekbones.