the foil tears easily

ruptures easily or
is prone to rupture

Is easily pierced?
Context of the exact danger...

..., the foil rips easily.
Geht ebenfalls.

Just a tip: "Folie" is usually not "foil", unless it's aluminum foil. It's usually something like "plastic film", "cellophane", etc., depending on the material.

pierce = (durch)stechen, lochen

Thank you, #6.
I am guilty of looking for the best word to describe what is happening, rather than giving an exact translation of the original.