> Do you think you will know if someone has their phone in their pocket or in a holster, and is turned on and recording? You will never know.

At least this says something about the intention. Someone who films with a hidden phone implicitly shows that they intentionally hid this from the people being filmed.

Filming with glasses is hidden by design. It gives plausible deniability to the person filming, so they can film covertly but pretend they weren't hiding anything.

In most cases this doesn't make a difference but there are some cases where the premeditation can make it worse for the person doing the "abusive" filming.