HAHAHA Yeah, used the MFLB in the back row in my early vaping days, few light puffs nothing too heavy in a relatively large and empty cinema theatre. My non smoker friend said it smelled like someone had weed in their pocket but not like smoking.
Done it twice now, recently on the thor movie, I think its fine if you exhale into your coat or something, but usually only if there is a lot of space, I would definitely not do it with someone right next to me.