Short version is I went to see a friend play last night and there were several musicians in the audience that I've played gigs with before.  All previous encounters with these guys at gigs have been positive with the exception of one, and that gig was just simply a trainwreck due to the way it was setup.

I was surprised to find that I got snubbed in a pretty douchey manner when I went up to say hello to these guys..they were not there getting mobbed by other people, or in the middle of talking to someone so thats no excuse.   Generally when people do that to me, as long as I have not already identified them as someone i don't want to talk to I will greet them warmly and engage them in conversation even if its only for a minute or two, especially if it's people I've played music with in the past.

Good thing is I am pretty thick skinned these days, so I just take that experience and file it away as "ok so, this guy is a douche, good to know for the future" and make a mental note to not do that to people who have not done me wrong or shown themselves to be annoying.  

Since you were not on stage you was one of the little people. I have experienced the same thing . They be afraid you going to pull some of their thunder away. That is the only explanation I could come up with.

not sure if serious but that could be...

who knows...musicians in general I've found can tend to be weird and cliquey I guess.

I snub idiots that ignore and/or don't comprehend the words "no trades", which are usually in my Craigslist ads.

Who knows maybe in the future one of them will need something from you, and you can remind them of that time.... and then pause, and be nice to them anyway, it will really confuse them.

I was at an "open mike" night last year when a kid tried sitting in on guitar.  The guys were doing some jazz/funk stuff.  The kid was pretty bad, but he was really trying.  When he got through, nobody said a word to him and he looked embarrassed.  
I know a good teacher and gave the kid his card.  I haven't seen him since then, but he's been taking lessons and I hear he's doing well.

There's no excuse for shutting down someone who wants to improve.

I have an old rusted out lawnmower deck and a pair of hip waders I would trade.

 

I absolutely snub people. Do you know how many weird mother fuckers there are?

I'll give a used condom and a half eaten box of Ho-Hos.