I don’t brake check people, but I do flash my brake lights a few times if someone is tailgating me. That generally makes people realise “oops, sorry, I was too close”. If they ignore that I slowly turn the cruise control down until they’d rather switch lanes and zip off. Funny how I’m only tailgated when there is plenty of space in the passing lane to the left of me.

The brake checks that the assholes do are when they actually brake to have near-collision vicinity to trigger collision warnings/autobrakes on trucks and busses, or to really rile another car driver up/collect insurance. But they forget that many people nowadays have dashcams (thank you Russian insurance companies!).