I had my own backyard outlaw field for 10 years. My homeowners policy covered me as long as I didn't charge for anything. So I never did, and we had people get hurt and no one ever sued. But, the risk is always there for getting sued.
Here is a video I made that covers a lot of what you should think about. We had an absolute blast with my field and made memories that will last a lifetime. I still have an obscene amount of paintball gear and could literally set up 20 players easily with all my gear. I also have 2 chronographs still. And air horns. Lol.