Plus those devices are more suspicious when pointed at you

Can't say I agree.
I have seen one of the pens and it's hard to realise it has a camera. Also, it's probably made for the times when people used to normally keep a pen in their breast-pocket.

That’s a pretty significant difference.

For me, honestly that's a good enough difference and I would be fine if someone were just keeping a camera on their head while in public. Although my expectations might change in a shared restroom with urinals.

Also, would you want a similar response to someone using AR glasses, not made by (and not selling video data to) any corporation?