Heh! It helps that the main manager is my future Son-in-law

Frankly...if smoking is not permitted, I don't do it. (But that's me.....)
Best thing to say is "hey, do you mind if I don't smoke" while waving your PV at them.
I wouldn't dream of vaping in a shop or restaurant (cafe) because you are very rarely in there long enough to do without, but if I go to a pub (bar) then yes I would ask first unless I knew they banned it (JD Wetherspoons in UK) where I might stealthvape.