I think sometimes its just a feeling you get talking to them.
I think anyone looking to place a glider should have many conversations with the potential new owner.
You can sometimes get a feel if they are off.
I agree if they start talking about babies before they even have gliders.
If they try to haggle price like they are buying a used car is one of the biggest grips I have. While I agree people should not make money off an older glider they are trying to find a home for they should not expect to get them for free.
We took in a glider that was surrendered and we started putting out ads an we did put one on Craigs( never again)
I got 43 responses all with a variety of comments back on why they didn't want the glider unless it was free.
My favorite one was "I can't afford that I'm only 10"
Comments like that you can't press delete fast enough.