[ceejayoz]

> You can't just stop suddenly out of nowhere for no reason without signaling.

You absolutely can; it's what you're supposed to do if a toddler runs out in front of the car, for example. Barring malfunctioning brake lights, if you rear end a suddenly stopping vehicle, you were at fault for following at an unsafe distance.

Most legislation about this (example: https://codes.findlaw.com/ca/vehicle-code/veh-sect-22109/) says stuff like "when there is opportunity to give the signal". Screech brakes, then signal.

[bryanlarsen]

In my jurisdiction, brake checking is illegal.

But it's pretty hard to enforce just for the reasons you mentioned. "I saw something on the road" is a fairly bullet proof defence which nobody can counter.

[mtreis86]

> for no reason

Kid in the street is a reason to stop suddenly

[ceejayoz]

If you’re too close to a car stopping for no reason, you’re also too close to a car stopping for a good one. The physics are the same.