Hi Chris (H),
Good question. Answer is if, the paint scheme goes over some glazing then I do not remove the masking whilst still not fully cured, but I do add a varnish coat as soon as is possible, and then remove the masking.
Secret really is not to allow the paint to harden (say a few days) but as soon as you feel you can apply a varnish then do so.
Paint continues to cure over hours/days, generally most by 24hours. It is down to finding 'that happy place' in the paint drying time and acting.
Cheers,
Bigkev