That was my first impression too, but after more thought I'm not as hard over on it. Some people just aren't as good at telling others what they think when it may be considered insulting. The seller here may have wanted to just say "no, you can't take it to another airport because if you do and something happens where I can't get it back to my airport, you may not only bail out of the deal but also stiff me for any costs incurred that should be your responsibility." That's perfectly reasonable IMO. But some may find it hard to say that to someone, so they try to think of other reasons that seem cut-and-dry like "I don't have a medical" or "liability" or whatever. But then the OP annoyingly keeps coming up with solutions to those... So, not NECESSARILY malicious intent. Could still be, of course.