Quoted from Per_:
They are held by the flaps etc. and adhesive effects. They should not be fixed entirely to allow temperature depending length changes.
I decided to add mine on the new machine for the same reason (in particular to protect the playfield monitor cover). Ball movement may change a little bit but I can live with this. JJP even offers factory installed protectors.
I also did one cut behind the airlock screen and put the stripes together with mylar (from behind). There will always be some "fine tuning" with the protectors as no two machines are exactly the same (especially from Heighway )[quoted image]
Exactly the same place where I made my cut