Again, it depends on what they have done, MAJOR or MINOR. If someone blocked the road, and it leads to a big traffic jam (which can happen) to me that would be a ban. If they crashed into another driver, and it causes both to f7, that is a ban. If the driver decided to use racial slurs etc, that is a ban. And there is a lot more on what is a ban and probably maybe warnings and kicks (being 2 warnings is enough). Probably...
Either way, for me, if someone did something bad, I would hope they have been reported and banned. There's been times when I knew where people crashed into them or overtook them when they did need to do. Heck, there were two trucks who purposely crashed into me and made it hard for me to drive. If I had a recording of it, I would send it as a report, and it would be a BAN. Simple as that. Hence, why banning is just simple and easy. Giving people warnings may help those who could not do it again, but there are a few people who feel lucky and will end up doing it again.