With my first rifle purchase through EE, I asked for the seller's full name, location, and phone number. Then I called and spoke to him and also googled his name with the town name. Turned out he'd been active in the local non-profits, according to local media articles. After that I was perfectly comfortable sending him money.
In my career I've been scammed by a person who would have shown up as a CONVICTED scam artist if I'd only Googled his name...Brian Penney in Edmonton if anyone there is reading this. I learned after that! Also Google the email address and phone number; crooks are often lazy and use the same one for a bit until it gets too hot.
When I sold my first gun on the EE (for over $1k) the buyer didn't ask many questions. But I'm honest so it was all good LOL.
***** FREE THE WEST *****
I asked for (and got) the PAL info off the seller the first time I used the EE. He mentioned it was "unusual" but didn't mind. I was new and overly cautious both of scams and of legal issues... now I've had numerous positive experiences with the EE and have met some great CGNers through deals there.
If you're buying a firearm, you're providing them with your contact info, address and PAL so I don't think asking for similar info is inappropriate. Doesn't hurt to ask anyways.
Cheers,
Kyle