Using the handbrake while the car is parked is universal, and in most modern cars the handbrake activates automatically, so it would likely cause actual damage to try and move the other cars with your own. It's also not uncommon for people to put their car in 1st gear on purpose when parked (in my experience, mostly older people who don't fully trust handbrakes) so you'd be unlikely to move those at all.

It wouldn't be legal in any case, although I suppose it would be difficult to be covered by insurance without video evidence. If it happens when you aren't there then tough luck, but if you saw someone touch your car while parking you would go to them, check for damage and if there is indeed any damage you would both fill a constat d'accident (standardised European Accident Statement) to let your insurances sort it out.