I have to say, when I was in college (and even now, non-agnostic that I am) I would not have been able to prevent myself from SOME smartass comment:
“Yeah, man! He sells the best weed on campus!”
“That’s the guy my mom was having the affair with, you bastard!”
“Damn smelly hippies.”
“No, but he’s HOT. Is he in Playgirl?”
Et cetera.
Can former agnostics join in if they don’t start witnessing? 
Back when I was a pagan and then an agnostic, I had some of the same problems as people around here. Most of the people I hung out with were the targets of the Christian-Right groups on campus. I remember a particularly surreal moment where a few polo-shirted khaki-clad young men came to help our gaming group put up our tables and, after asking us about what we did, inquired as sweetly as anything "So you do realize you’re going to Hell, right?’
Yeah, buddy. Whatever. :rolleyes:
Much more fun was had in general by the rotating street preachers. One of them informed me that I was going to Hell (this is a common thread, y’see, among some people).
“Whyever?”
"Because you’re – " Here he had to consider. I looked like a pretty clean cut girl with long hair and a cheerful smile. “You are wearing the garments of a man!”
Sure enough, I was wearing a pair of blue jeans. “Gosh,” I said, sitting down next to one of my friends. “These jeans are going to send me to Hell?”
“Indeed they are!”
Had I been the woman then that I was now, I might have screamed, ripped off my blue jeans, and run away. Instead, I looked at my friend, shrugged at her, said “Oh well. In for a penny, in for a pound!” We then proceeded to make out. 
I met plenty of people that I just… didn’t tell. I didn’t want to get in to the old conversation. No, I don’t believe in your god. Nobody did anything bad, I wasn’t molested by a priest, I just don’t. Believe. In your god. And especially not in your religion. No, that doesn’t mean I have no morals; believe it or not, we can look logically at human behavior and decide what seems to be Good and Bad. Two thousand plus year old books do not have a lock on the market there.
Admittedly, some of my beliefs in that arena have changed since then, but that’s a topic for another thread, if at all.
Incidentally, just as an aside, pagans were lumped in there with atheists as not being citizens. I was fit to spit nails when I heard about both: whatever God or gods you do or do not believe in should have no influence on such a thing.