It's not just clip on/clip off! It dislodged mine a while back and needed a lot of brute force to 'clip' it back in!!
The secret with speed bumps is to jab the brakes just before you get to one and then lift off and the car naturally springs up!!!
Often the impacts sound horrible but they result in very little damage.
When a friend of mine was studying in Portsmouth I went to stay and I scuffed the splitter reversing in to his place. Driving out the next morning was torture. No matter what I tried the splitter caught and made a horrendous noise. People 100m down the street were looking round to see me sheepishly trying to get my pride and joy onto the road....