Correct me if I'm wrong, but brake-checking, when proven or obvious, is already a ban-able offense. Moderators reviewing reports ingame can see how fast players are going and therefor identify a sudden drop in speed for no viable reason. Deliberate brake-checking can be classed as §2.2 - Collisions: Causing or attempting to cause a collision with another player intentionally or due to negligence.
Now, unfortunately, these cases are not always very obvious, hence why you might have had the experience in some cases that Moderators prefer a kick over a ban. Such cases depend on various factors, including the amount of players nearby, the traffic situation in general and the safety distance between trucks just to name a few. In web-reports especially, there isn't often enough evidence to support the deliberate brake-checking claim.
At the end of the day, just like in real life, the person rear-ending a car in front is often perceived as guilty until proven innocent. So, to avoid being brake-checked, try to increase your distance to the truck in front and drive passively. That isn't always easy, I know. Especially when people seem to deliberately brake check, but just don't do anything to escalate the situation further. This style of driving has helped me avoid finding myself in situations you are describing.