I occasionally like to chase clouds, but most of the time I'm more on the flavor end of things. I do drip max vg, but unless I'm outside, I keep my exhaled vapor low so it dissipates quickly. If I'm in a crowded place outside I dont turn on the fog machine, and I blow my vapor strait up or strait down to keep it from becoming a nuisance. Blowing big clouds in a public place could be the equivalent of yelling "FIRE" only instead of yelling it you are creating "Smoke" (yes, I know its not smoke, but someone who doesnt know sees the fog rolling in above the registers and pulls the fire alarm.. stranger things have happened).
I vape everywhere except accept in clients offices (face of the company and all that), around kids, and where it's posted that vaping is not allowed. But I'll keep the clouds small and blow them strait down. Not really stealth vaping because I'm not couching down or hiding my mod or anything. I do this not because I dont want to get caught, but because I dont want to be a nuisance. A little respect for the people around you. In the bars (you can smoke in most bars in Texas) I dont hold back. One time our waitress kept coming by making yummy noises, lol. She mentioned at one point that she enjoyed coming by our table because it smelled so good and asked about the table we had turned into a mod stand (5 vapers with a setup or two each, most dripping so we just laid the juice out on the small round table so we could sample each others stuff - I shoulda got a picture).. lol Great additional benefit - better service because your table smells better

We went to the driving range and a bunch of our group was vaping - a few blowing big clouds - the only thing they did was kick on the fans
With it being a grey area in most places it turns into a situation where if you aren't bothering the people around you, you probably wont get harassed about it. Blowing huge clouds in the market seems like it could cause panic, so I'd steer away from that.. you are at the checkout line, just wait the extra minute and take it to the parking lot (though they were probably doing it for the attention).
As far as your boss goes, try having a conversation with him if he/she is reasonable. see if he will do a "if I dont see it" kinda rule. I hate wide rules intended to make the minority of idiots not doing stupid things... I can see how it would be hard to enforce a "no volume vaping" restriction, because someone will inevitably push the line.
Alternatively, maybe have a "your going to ruin it for the rest of us" conversation with the offenders. I've had to have that with a few buddies at times... its not ok to chase the clouds in the cheese cake factory...