Comment by JCattheATM

> The gendarme might actually arrest the attacker.

So might the cops we already have in such places.

> The security camera will do nothing (but record).

Exactly as intended.

> And having the policeman standing there is about as much a deterrent as a "Smile--You're Being Recorded" sign.

This seems like a weird thing to say. Cops are more of a deterrent than a gendarme.