I've been following this but until now have been unable to reply. Can I tell you my experiences?
1 I practiced in my garage, shooting with my back to the window wall and at a 2' target at about 8m distance. There was a stop net hanging behind the target. One day, I forgot to alter my sight and missed the boss. The arrow went straight through the stop net and the metal garage door, leaving the fletchings inside the garage, and hit my car in the drive.
2 A new member at our club shot an arrow with a
compound bow but released accidentally with it pointing a little but not excessively high. The arrow landed about 450m away. He didn't mention it to anyone so is now an ex member.
3 Shooting indoors at 20 yards, someone's bouncer came back the length of the hall and stuck in the skirting behind the shooting line.
The possibility of these things happening was small but the consequences had a person been where the arrow went could have been an avoidable serious injury or death. Think about that before you set up your range, after you have and regularly afterwards.
I now practice in the garage with two stop nets, set apart by around a metre and lean 19mm ply sheets against the garage door behind both of them. I have shot an old arrow at this to check that it stops the arrow and it is effective. It is very important that the stop nets are free to swing and are not taut - ie make sure that the boss is not sitting on them. I think that was one of the issues that led to the hole in the garage door.