I'm not brave enough to do that. I use my hopper at 4 and blow out huge clouds, I wouldn't feel comfortable doing that in a theater. Besides the legality aspect, I feel uncomfortable blowing huge clouds of vapor around other people's heads and in their line of sight. I wouldn't want someone doing that to me with an e-cig.
I could see myself using the hopper at lower temps without a smoke buddy, as long as there wasn't much visible vapor I could hold it in long enough to make most of it disappear.
The way I prefer to use it, the hopper just puts out clouds that are too big and dense in my opinion. I tend to be overly cautious too.
If you can get away with it, that's awesome! I love hearing about all the crazy places people vape in public!