Having a rather "pointy" head (think of something like Patrick Stewart's head), all bicycle helmets I've every tried on tend to have contact with only one point at the top of my head.
Now my idea was to cut a little bit away from that rigid foam at that location. Let's say 1-2 millimeters at the size of a dime.
My local bike dealer told me that the whole helmet has a fine-tuned structure that completely breaks down when removing even the slightest piece of rigid foam, no matter how small.
While this sounds strange to me, I'm confused right now.
Therefore my question is:
Does a bicycle helmet still has protection when slicing some 1-2 mm from the inner rigid foam at a size of a 1-2 cm circle?
(I'm from Germany, in case this matters; maybe our helmets here are different)