Well made post!
A couple of additions.
A parent could go to a local pro shop and do some research. Most shops will take the time to educate a p[arent in hopes of future sales. Ask in depth questions about eye protection and paintball gun maintenance.
A parent can ask the local field owner for a "mentor/tutor" kind of person. Most field owners know an experienced player or 10 that would be willing to take a new player under his/her wing and get them properly introduced to the sport. Dont just drop them off trusting their judgement until you are comfortable. Most parents are encouraged to stay and watch, most fields will loan out rental goggles so they can go see what it is all about, and maybe even play themselves. As a parent, it would be benficial to go and try it for yourself, to have a better understanding of what it is like and the risks involved. There are too many parents just buying equipment and dumping the kids off so they have an afternoon by themselves, then wonder why they got hurt or in trouble. Many kids play in their own back lots or woods. Parents should be well aware of exactly where they are playing, how they get there, and if it is legal for them to be playing at that location. And if they are playing outlaw, they should have at least one adult just watching for saftey concerns, I.E. wearing masks and proper barrel locking devices being used at ALL times.
If you are a teenager wanting to play ball, do research, and involve your parents in the process. Educate them as to how SAFE it is, and explain to them how you will be responsible while playing. Work extra chores for paintball money, and respect their wishes on how and when to play.