There are risks in everything you do, it comes down to how risk averse you are. Yes, someone can dob you in if they feel like it, yes you leave yourself open to extortion by the BiB if vaping, yes there have been reports of undercover cops videoing people vaping at bars (they don't report you to immigration, they will pick you up there and then and show you the video so you know they have you bang to rights), yes they are still banned with the penalty of up to 30,000 Bht and 10 years jail (obviously not going to get that just for getting caught vaping in a bar), yes people, Thais and foreigners, continue to vape.
Your choice, but if you do get pulled up, don't just bend over but don't be a dick about it either:
https://www.thephuketnews.com/frenchwoman-deported-for-vaping-70535.php#:~:text=She posted bail of B100,was to collect her passport.