I can relate with everyone's experiences and frustrations. I also am very particular about who I let fish. Close family members, most of whom live far away. That way I know my aggravation will be short lived. And only VERY close friends.
I'll give my 2 cents worth, maybe it will help solve some of your problems. I would add some rules. I would make it mandatory that if not fishing with lures, to you MUST use a bobber. They can compensate somewhat for depth, if they decide they want to fish deeper. I would also make it the smallest bobber possible for the rig they're using. That way the smallest of strikes are detected.Also long shanked hooks only, with the barbs removed. I would also go as far as making the rule that they can bring their own lures, and upon inspection can be used, but I would provide the fishing hooks, all theirs not being aloud. Kindly explain your reasons for the types of bobbers and hooks used.
The thing is many people dont know any better.Once upon a time, I used to not understand the different options, and the reasons behind them. And there's others that dont care or all ready know everything. Anyone defying or arguing with the rules......you're outta here and dont come back.
For what it's worth, I occasionally have people that I know, ask ifn they can fish. I know the one's that will turn it into a free for all. I turn the tables. I ask to use their pool or bbq pit. That I'm going to have some friends over to their backyard. It's always a no-go.I tell them how much money I've thrown in that hole, and they get a funny look in their eyes.
The ones that dont have a pool or BBQ pit, I ask to borrow their car........
Anyway, it can be a difficult situation to be in. Do not be afraid to change the rules as you go along, and as needed. Always remember you're trying to be kind. Your kindness should be reciprocated.It's your ballgame, and you do make the rules as you go along.
Sorry about the rant!