Personally, i think that if you start to allow accountsharing, there is no way to separate it from multiaccounting.
Though, this is up to chadz.
EDIT:
Unless ofc if its by game mechanics.
And for the love of god, if anyone develops a tool like that, let the devs know. Bans are always funny to laugh at, but unnecessary ones are rather sad. (accountsharing is not legal (yet))