With most organizations you have to fill out paperwork, do an online/paper, phone and/or in person interview and go for about a week of training on how to handle and work with the dog. Though of course there are bad organization that don't do all that and just ask you to hand over money, and people who don't care for their dogs properly. (Just like with normal dog owners there are good and bad ones) However for the most part many places are very thorough in making sure the person is able to care for and work the dog properly.

Most will also take the dog back if they find the person isn't handling the dog properly.

My dog definitely prefers work rather than staying at home in a crate. Whenever her vest comes off she does everything else a normal dog gets to do (Go to the dog park, go on walks, do fun sports and trick training, chewing on bones and playing with toys, meeting new people, ect) it's only when the vest is on that she's working.