I'm in LA- and I don't buy drugs at events as a rule, but I've scene many people have a bad night after they have (usually bunk, sometimes pipes or other). I certainly don't think counting on a "good scene" means it's smart to buy drugs at an event- doesn't matter where you are, buying drugs at an event ups your risk for harm.
Yes, it does up the risk a little but not nearly as much as some people here seem to think ime. If you do have to or choose to buy at the event for whatever reason just be sure to look up the good pills in your area online before you go and only buy pills that are known to be good.