This is a very good idea. Currently I can hardly justify the price, but for keeping the whole family organized for say 50$ a year, might actually make sense. The delegation feature would come handy here.

As a long time user, I'd probably have to say that this won't work.
As there is the highly probability of misuse.

How would RTM staff know 'Who' is family?

As it is, I've heard many people complain about the cost of RTM. It would be too easy for a group of people to fake being a family just to save a few bucks.

Just my 2 cents fellas.

My request is a varient on this. I'd like to be able to organize with my wife only. Perhaps she could log into an account that we share. We'd have different user names on the same account. I'm not sure what other functionality would come with this, but perhaps it would be harder to exploit...

I'd like something similar. Perhaps make it so a sub account can only use lists created from the main account