1) it can’t really tell reliably.

And

2) correct.

You can manually disable the auto—trigger mode in those situations though (bypass mode).

It also doesn’t like anything conductive - so anything coated with Mylar, any kind of conductive dust or debris, etc. is also a crapshoot.

Very much edge cases though, unless you’re dealing with a lot of randos. A workshop I used to share had a wall covered with sawstop ‘trophies’, due to people doing weird stuff.