I have only had one request and that was to play a player if I select him in squad. So that he wouldn't miss out on games and then not even get an international match.
Personally, if I got a request like you guys did, I would assess it & determine the importance of the international match & only concede to their request if it could be done without harming the national team. When I have my NT Manager hat on the NT comes first - if a player is already fatigued, I won't play him. But if I had a request to rest a player because it would fatigue him for some upcoming club match, I would probably agree if it was a friendly coming up, but if he was in strongest squad & it was for WC quals, then most likely I would still play him.