At the point I noticed a problem; I saw a sign face clamped to the table at one end while someone was at a 45 degree tilt trying to pull the vinyl off. I had to try something... I think this might also work with protective plastic that has been baked on. Due to the uniform pressure it applies on the vinyl, it might release the adhesive before tearing the vinyl. I know it is a simple idea. But, I wanted to share in the case that it could help.
Cheers!