I’ve been surprised by the number of “Aircraft for Sale” that are in the Air. The Aviongoo website has a link to FlightAware whenever there exists a recorded registration number. For example,
aviongoo.com/aviongoo/faa_in … num=N515GM
At 3:20 EST N515GM appeared to be getting close to the Maine coast. I thought most of the aircraft for sale would be grounded - silly me.
Is that “in the air” knowledge an advantage, disadvantage or doesn’t it matter when you know the plane is for sale?
No different than living in your house when it is put up for sale or driving your car while waiting to sell it.
If it’s in the air, you know the engine works. 
Great point!
I made an agreement (and deposit) to trade my pristine Cardinal on a Saratoga several states away. It had no record on flight aware. When I flew to see and inspect it, I decided to bring my cardinal home instead. I am looking at a Lance the same distance away - have decided if I am to make a move I will have to buy the new bird and then sell my cardinal - and it encourages me that it is now flying IFR regularly. I can also compare airspeed and climb with the present owner’s claims.