From a cellphone’s perspective a crash = extreme acceleration with different vectors vs a dropped phone, they can also listen for broken glass etc. So even with GPS off that’s detectable.

iPhone 14+ and Android 12+ https://en.androidsis.com/How-to-activate-automatic-accident...

Other drivers will phone it in. This isn't a concern for me at all, but I suppose it could be if you lived in a low population area.

iPhones actually can. I'm guessing some Androids have an equivalent.