Can you somehow send a trade request knowing only the other player's ID?

I'm pretty sure that this has been asked a lot of times but, seriously I've tried to search for it and I couldn't find any post related.

I've just received a trade request from someone that got into my forum store and I was wondering how did he managed to do it without being allies.

Thanks.

You shouldn't be able to find people with just an ID, but there are ways around this...

1. The simplest and neatest: You have a spare ally slot. He ally codes you, clicks on your pending ally profile, initiates trade, removes the ally request, done.
2. Does the same, but with a person you previously traded with. Maybe you posted on his wall, and he can track you done(really unlikely, but possible).
3. Maybe he traded with you before or is familiar with you, but you're not aware of it.

Oooh... clever. It was option 1. Didnt realize that meanwhile your ally request is pending you can access the other's player wall.

Thanks!