Originally Posted by JordanWalker

You can 'mislead' a lounge receptionist and be able to get in that day of, but they will still note down which FFP and # you used. Along with a scan of BP.

And then when that lounge (say AA) goes knocking on CX's door for that lounge entry's cost....you can bet they will find out that your membership # was supposed to be on holiday. Will they do that to everyyyy lounge visit? Prob not. But is it worth the risk and having your status/miles suspended? Well, that's up to OP....