I think there are tons out there. For years I was stupid and missed very obvious come ons. Now I am much more aware. If I am open and looking all I have to do is have a bulge or semi, thin shorts, give a quick glance at his crotch etc.
However, I have had the most experiences while traveling and married guys just want something anonymous and quick and are easy to invite back to the room.
Many also have these fantasies that they act on when traveling. I guess the intrigue and never see you again philosophy comes into play. Some odd requests too. About 3 times back this guy asked if he could shave me after he drained me and I thought what the heck let's get a little freaky. It did get me hard again I must say.