I've always thought the most fascinating part of such sales is if and where backdoors would be put into aircraft and other military exports and how they would be utilised in a scenario. It think I read somewhere about France doing this at one point with fighters.

For example there is no way I'm gonna believe a Saudi F15 doesn't have something that the US could manipulate to its advantage if it chose to.

Of course building a backdoor would mean if an event found it, then could also utilise it. And it would be bad for business if it was found.