I wouldn't be afraid of a car dealer especially if I were buying a used car.
I'm sure they come with a warranty of some kind.
All trade-ins would be checked out by mechanics, they want to know what they're getting into when they give a price....look for issues.
I'd be more leary of a private sale and that comes from someone who's sold the last two large SUVs privately.
You never know why someone is trying to *get rid of* their vehicle.
Our explanation was easy, we were downsizing a bit (Suburban to a Tahoe--they saw it) and knew we'd get more selling it outright than trading it in.
Plus, they knew where we lived, they could come after us if there was a problem. No problems!