I have my hand open when I shoot so I just have my sling loose just in case. I accidently hit the trigger on my release the other night trying to get a mosquito. I'm pretty sure I would have dropped it without the sling.
Yes but I don't think it is a requirement. It was more of an extra precaution and to make the bow more like my own. I like to customize stuff and it drives my wife crazy.
I use one and it helps a lot with my grip form. Before using a sling I would instinctively grab the bow right as I shot an arrow to keep the bow from falling and it caused my accuracy to suffer. Now that I have a sling I can use a nice loose grip and let the bow rock forward after a shot without worrying about it hitting the floor.