You don't need a fee for you to manage your data use. You need a fee if you want Verizon to manage your data use. You can also go on Verizon Plan and activate safety mode, which is free, and that prevents overage charges.
the only time I've had to pay was when I had to get family base on my account. (for my younger brother) the feature itself does A LOT more than just limit the data usage. You can set up time limits and stuff like that which is helpful if your dealing with a school aged child.
If its a matter of someone just not listening to you about the data usage just take the phone away if you don't want to pay for family base.
I totally agree with you. If other carriers give unlimited data why won't Verizon?.They charge me so many overages and now they are killing me wanting me to take another plan called XL without mentioning the fee for it.