At least the EU is somewhat privacy friendly here (excluding the Google tie in) compared to whatever data sharing and privacy mess the UK has obligated people to do with sharing ID pictures or selfies.

Proving you are 18+ through zero knowledge proof (i.e. other party gets no more information than being 18+) where the proof is generated on your own device locally based on a government signed date of birth (government only issues an ID, doesn’t see what you do exactly) is probably the least privacy intrusive way to do this, barring not checking anything at all.

It is complicated. It is not technically always, but in practice is may very well be. As this page (in Dutch) notes that, unless the driver can show that ‘overmacht’ applies (they couldn’t have performed any action that would have avoided or reduced bodily harm), they are (at least in part) responsible for damages. For example, not engaging the brakes as soon as it is clear that you would hit them, would still result in them being (partially) liable for costs, even if the cyclist made an error themselves (crossing a red light).

Because the burden of proof is on the driver, it may be hard to prove that this is the case, resulting in their insurance having to pay up even if they did not do anything wrong.

Robot Operating System maybe? Might be an acronym for something else too, though.