This is of course a generalization, and details matter, but if we're going to err on one side or the other, erring on the side of the person being involuntarily affected vs. the person taking voluntary action is probably the better call, at least until all the details emerge.
And yes, pitchforks tend to come out long before all the details emerge, but that's a bigger problem (that we do need to solve)..
(Disclaimer, I have no idea.)
Although like anything else in life, "be nice, be respectful" are some pretty good rules to overlay on whatever approach you take.
Bonus advice. Ask about their mother.
Call yourself lucky then. It's of course anecdotal but I have seen both extreme ends of the spectrum.
Two, both physically very attractive, friends having ass-grabbing competitions at the club and both taking very attractive women home.
On the other hand a shy guy who was pulling all his confidence together and chatting up a girl at the bar, got shot down big time and from then on had the reputation of being a "creeper".
If you ask women, they will usually tell they want to be approached neither on the street nor the store, nor library nor public transport. They reinforce that idea by by wearing earphones, only staring at their phones, evading eye-contact.
So that leaves bar and clubs, you think? Well. they also do not like to be approached these places because they went to the club/bar for dancing/drinking with their friends.
I think this is an extraordinary case and it's not likely you'll be "cancelled" for flirting. But when anyone in the world can publicly slander you, it's your word against theirs, and the only thing you can really do is report their tweets...
Which tends to just be another way to restate that happy outgoing/extroverts are going to find it easier, because they are unintentionally sending signals.
Are going to find it easier because they are more attractive (or, attractive to more people).
And so ends civility in 50% of your social interactions.
It seems like part of flirting is being able to figure out the other person's response and either stopping the flirting or know that they're enjoying it and keep flirting.
(I'm saying all this like I'm an expert or something but yeah, I could use a 'Flirting For Dummies' book myself :) )