If you're charming enough, it might work, but if you're charming enough, you probably don't need tricks like these.

This can work in rare occasions, but has a high probability of coming off as creepy.

The entire reason for dating sites, more or less, is to create a list of people who are open to a cold-email for dating and facilitate the process.

If it is entirely out of the blue and you have nothing in particular to discuss, it might come across a bit weird or creepy. Expanding your social circle is probably a great start though.