Yes, you still have to release the animal. The raccoon I caught was young and naive. If it had been a big granddaddy coon, it might have been different. My husband wanted to shoot it out of the tree but after I saw that it was young, I wanted to catch it instead.
Sure; most small animals just want to run away. I do think putting a cover over the trap before releasing is a worthy precaution with some animals.
I have always done humane trapping, mostly feral cats in the last few years; but with such as raccoons it is tempting to do otherwise; they are truly destructive and they reproduce prolifically like illegal aliens!