The problem here cel is that having someone have permanent access to your account, makes it far too easy to abuse the purpose you want to use it for, it's not about not understanding the reason you want to do it, it's about looking at the ways that others will abuse it.
So many players on .net already make complaints that new worlds are full of co-played accounts, and 24/7 sat accounts in order to retain rank, why help to facilitate such things?
And the reality is, there doesn’t even need to be a change made to accomplish what it is your looking for. When you log in, if it says someone is sitting your account, would you like to end it, click yes, then immediately go in and re-set that sitter, then continue to play, that way you’ll never forget to reset your sitter.
Have you thought of the negative impact of a permanent sitter, that can log in at anytime they choose, without having their name removed from the sit?
If someone sets a permanent sitter, and for whatever reason they get into an argument or a spat, their sitter keeps logging into their account just to annoy them.
They won’t even be able to get into the sitting menu to remove the permanent sitter, because the player will just continuously log in over and over and over again, so you will keep getting booted off the account.