We all need our motorcycles to carry stuff for us sometimes, and knowing how to do so safely and securely can sometimes mean the difference between a fun trip and being pulled over on the side of the road collecting the stuff that fell off.
Remember, these things are under tension. When you snap them together and pull the straps tight they're very secure, but the larger ones have an especially strong pull. If you release the clips without first relieving the tension on the straps you might be in for some injury. Loosen the straps first and THEN undo the clips.
Realize that not everything that sticks out of your motorcycle is a good spot to tie something to. Turn signals are unfortunately very commonly broken off like this. I've seen people try to secure their motorcycle to a trailer by the bike's turn signal (predictably, it ended poorly).
Frame parts, luggage rack parts, passenger peg mounts? A-OK. Plastic parts, fairing edges, turn signals? Don't tie anything to those for any reason. At best you'll end up with broken plastic, at worst you'll end up with your stuff gone or a crashed bike.