Yeah, but you have no idea what this guy has done to his console.
You don't know for sure that it hasn't been modded or the seal on the case hadn't been cracked open (because that will void the warranty). If either of those have been done and you don't notice or buy it anyways, you're screwed.
If the system has been refurbished you also don't get your warranty (since they have to open the case to do that). He can still say he has all the original paperwork as he got it but that doesn't mean it isn't refurbished.
The system could have also RRoD the day before and he just does the towel trick before you pick it up to make you believe it works. Yeah, best case you still have the warranty but you still have to go through the hassle of sending it in and waiting.
Call me pessimistic but people are scum and they will do anything to screw. Sure, there are good people out there but just assume everyone isn't.
