Oh - I've been following the Pakistani F-16s debace now for a decade - are you saying that US has loads of long simmering disputes over kit they've promised/sold/not delivered?
I'm saying that if you were presented with the sort of terms and conditions that are standard in your average defence equipment sale you wouldn't buy whatever it was you wanted to buy. The US demands to conduct regular inspection to see if you are storing kit the way they want it stored, that you haven't on-sold it without permission, are using it the way you said you would and once you're finished with it dispose of it the way they want you to dispose of it. And if you want to use it in a way the US disapproves, or even don't pay your parking fines in New York, the US will cut off support for the gear.