If ATC want practice PANs for training purposes it makes absolutely no sense (nor is there a requirement) to call them up beforehand and arrange it:
Much more sensible for the pilot to listen out on 121.5 for a short while to make sure there isn't a real emergency kicking off, then hit them with your 'practice PAN ' call.
And then sit back and listen out as the guard police (usually yanks) moan and whinge from the comfort of their CAT at FL360.
Cusco.