I think there are sometimes when etiquette is just not a primary concern. I worry about etiquette in dealing with normal people in everyday situations. Rudeness or odd situations definitely come up in those situations, and etiquette should not be abandoned then.
But honestly, if someone was coming on to me in a pushy and creepy way, they get a big "Get the F away from me" from me. I don't care about etiquette in that case, I care about making it extraordinarily clear to that person that I don't want them to have anything to do with me. That may be retaliatory rudeness - I don't think so - but I dont care either. I dont think getting rid of someone who has crossed certain lines requires you to be unfailingly polite and, frankly, from some of the suggestions here, passive.
I have to agree.
And any comments of "but he wasn't actually a threat in this context" don't hold any water with me. As far as I'm concerned any man trying to pick me up in an inappropriate way, or after I've expressed any disinterest is a potential danger. DF did not understand for the longest time how the unspoken threat of sexual violence hangs hangs over these interactions. He does now, after years ago when he actually watched me handle someone who was (inebriated and) potentially dangerous.
This is not, of course, to imply or suggest that all men are dangerous or active threats in this way. But the reality is that it can go from 0 to 60 in the blink of an eye, and you never really know who you are dealing with.
When I was 19, sophmore in college, my dorm was in a bad neighborhood. As a freshman girl and I walked to the subway (at 9am no less) a 20 something yr old man made some explicit pick up comments to us as we passed. We said, politely, that we weren't interested. He got up and followed up. For 4 blocks. Stayed about a quarter block behind us and yelled about all the stuff he was going to do to us. Until I stopped, turned around and yelled back some explicit stuff of my own. He then slunk off.
Etiquette just didn't matter there. Our polite refusal simply intrigued him.