These two rules do not have the same status in non-refereed matches as a moment's reflection would tell you, and here is one national association's opinion:
Foot faults may only be called by an official standing on court or by a chair umpire. Players may be
requested to correct their foot faulting problem by a Referee or Court Supervisor, who will require
the player to make an effort during the match to rectify the problem. The receiver may not call a
foot fault against the server.
Originally Posted by blakesq
do you inform the other side that you intend to strictly enforce the "in" or "out" rule on tennis balls, that is, if the ball lands out of bounds, you will call it out?