I would agree, best to keep within the area and not branch out too much. As for medicine there is also a liability and regulatory aspect to cover as well.
My counter for that would be, what if you grabbed enough people to be a team and practiced like that and had no intention to go proffesional, would the skills you devolope be suffcient for just friendly games either with your freinds or other people? Given those people probbly only did it the same way as you. No illusion somone who does basketball as their main source of income and job would be better at it than somone who just now and then "shoots hoops". Not discounting the proffesional players are universally tall and probbly would dwarf you.
Recalling back to how i learnt basketball in school, the teacher introduces rules when relivent (ie can only dribble while moving for a limited time when they introcue you to the dribble, tell you its non contact or what have you when you start doing games so fourth) and only showed you how it was done once. I dont know if they would have corrected you if you did it wrong or not though. thats how every sport was done. This is for children, and this goes from primary to secondary school.
As for injury, you can get injured doing anything, you can only mitgate it in some ways and in general common sense would prevail for that one. You could for all intents and purposes designated somone as a safety officer to basially live and breathe that. Like if we do bring up american football, there isnt much you can do to mitgate those injuries, same with rugby. (both get compartively high injury rates and serious injury rates compared to other sports) Those are probbly inherent in the sport and its rules. (hell at least in american football you get armour)
Addendum: As for injury as well, i would honesty prefer it if somone had a first aid certfiicate, everyone should have one of those anyway. Even if its just CPR and the recovery position.