Is it the mount itself that is regulated or the way it is used? A small piece of picatinny rail on a hard hat would be great for attaching a flashlight.

First bear in mind that the colors I fly are black, red and gold.
It is the mount and the way it could be used (not the actual use). Owning the mount and a flashlight would be assumed to be a preparation for mounting means of target illumination to a gun. In Germany the preparation and the actual mounting are against the law even if the gun is only airsoft. Usually the law gets people who buy similar mounts for their bicycles and get caught by LEOs.
The law is intended to protect us against criminals using gun mounted flashlights or lasers. I will refrain from discussing that law or make sarcastic comments about it.

I would rather not have a P rail on my hard hat - rather heavy and cumbersome compared to mounting a headlamp with elastic bands to the clips integrated into the attachment points for the inner suspension of most quality hard hats these days. Of course, it would look incredibly tacticool!

Similar to suppressors over here. Ditto on comments

Sounds like I need a new hardhat. The only mounting options mine has are a couple of about 1" slots for adding hearing protection.

https://www.fenix-store.com/fenix-ald-02...ASABEgIci_D_BwE


The link above features set of four clips which join an elastic band to the brim of hard hat. Similar rigs are available from other suppliers. They work pretty well in my experience...

I was thinking they were built into the hat. I split the difference. Streamlight has a helmet mount for their sidewinder light. With a little bending, it will work with hardhats. Ideal would be a light weight mount to allow using the Fenix PD35 I EDC instead of an additional light.