Depends on how you say it. If you say it with winky eyebrows, biting your lip expect being perceived as a creep. :^)
It really depends on the situation. For example, a complete stranger who was introduced to you by a friend, "tu" can be used safely most of the time. If you're by yourself going up to a stranger in a public place, "vous" is probably best until you're in the conversation for a while and ask if you can use "tu" (or until the person uses it first).
I suppose it would be ok for young persons - if you are young as well. Where the line for youth is drawn is a mystery though (I'm learning French). But generally you do not address someone unknown with tu, you use vous. As you have chatted a while you can ask if it is ok to tutoyer, that is call each other tu instead of vous.
The est-ce que part is good.
Yes you could. Depends on context. A stranger you meet for the first time and who wasn't introduced to you for example.
Of course this doesn't really concern the locations in which the purpose is mainly meeting an flirting with strangers (nightclubs and such). But as a foreign speaker using "vous" even though you could use "tu" is not as likely to surprise, and people will correct you if they want to informalize the conversation.