I get them too, from random girls who ask if I'm online. I say "no" and block them.
If you don't know the person, it's best to block them to avoid issues. They could be criminals or people who take their clothes off to get your credit card details. Best to block them, I say.
Sorry, lmao.
It didn't feel like such a bad idea to troll you with one or two lines before revealing who I really was at first.
I also didn't think twice about the possibility of you having forgotten our lovely PM
I generally don't block on the off-chance I would mistakenly filter out somebody legitimate. However, at the same time, I don't click on any links that they might supply.