Someone is trying to buy BTC from me and pay me with carded WU transfers, will this put me in trouble as a receiver?
I think it depends on the amount you're about to receive, cause if it's too much, then your bank is likely to question where the money is coming from. I don't think you have any problem with WU themselves, they are just after doing their work which is getting the money transferred to your bank account. And another thing is whether the person you're selling to is trustworthy, so that you don't sell your coins and end up getting scammed without receiving anything at all.