Of course I started behaving more carefully around him, and a little more carefully in general.This, I believe, is the wrong way to go about it. To me this seems like some sort of culture clash and in my opinion staying silent is the wrong way to go about this.
If I notice someone getting offended by my profanity I just tell them that they were not the target of that profanity and that I have no 'beef' with them. I haven't ever met anyone with whom this was a problem. I usually make a pretty good case for open communication, depending on sobriety of course. ;)
I believe the onus is entirely on the guy who is trying to be charming (if that's what we're talking about, as opposed to simple catcalling sorts of harassment) to notice when the object of his wit does not reciprocate with a smile and a kind word and to move the fuck on before his behavior gets creepy. I suppose I'm agreeing with you, as not smiling is a pretty clear form of communication - no rings or shirts or pepper spray are required.
I think the point of the "getting hit on all the time sucks"-argument for anti-discrimination rules was that even if all the guys who hit on a girl stop it after (instantly) seeing that she isn't interested it would still be a lot of input which "sucks". So the case many people skeptic of anti-discriminatory rules saw was that a girl gets hit on all the time and even if they all do so in a civil manner, the one unlucky guy who represents the 'final straw' to that girl then gets kicked out. The examples I put up for showing that you're not interesting were aimed at communicating that before you get hit on. A rough analogue for this might be a spam filter - You don't have to manually decide whether or not something is spam by reading it, you don't have to read it in the first place. :P
Harassment is obviously a reason to warn somebody or - if they repeatedly harass someone - kick them out of the event. That said, I think 'catcalling' is very nuanced, couples or people who know each other for $random_reason can catcall each other in play and fun, you can also do it in a sarcastic/parodic fashion etc. The only thing I'd generalize about catcalling is that you probably shouldn't do it to someone you don't know (and of course not to someone of whom you know that they don't like it).
But in general I think pretty much everything I said here can be succinctly shortened to "Be merry, have fun and if you feel there's a problem - talk about it - just don't do it behind someone's back."