I understand that you're implying it's somehow "dodgy" but I don't understand what does that mean for me, a buyer?
The only case I can think of is if those guys bought it with some stolen CC# etc but it's Apple's responsibility to check the seller's ID at the sale, they cannot claim it's mine.
What it means for you is you present stolen goods to apple and you think they're not going to take it off you/call the police? It could have been credit card fraud, could also have been jacked out of someone's trunk. I just can't believe you'd buy something in that situation - would certainly set off alarm bells with me - i mean, i'm sure you got it for a very good price, right? and so what if you checked his ID - against what? it wasn't even on the reciept - you told us that much yourself!