If they find out, yes. A lot of the time, I think people who are given promo material via ST member end up selling it online. I don't think any ST member has been kicked off for selling materials yet.
Yeah, usually when you see ST stuff on Ebay it's in small quantities which would indicate it's stuff people recieved from the ST, there's not really anything wrong with that I guess. Once in a while though you'll see whole bunches of stickers/samplers/flyers up on Ebay which is probably a ST member going for some quick cash. I haven't known anyone that got kicked off the team for this, I haven't been on the ST for very long so I wouldn't know, but I think the number one thing the ST looks for is selling of ST t-shirts, that's an instant ban from the team.