Twice this year, parents have inadvertently merged their parent account with their student's account. According to Canvas support Chat, when the account registration was clicked for the parent, the student logged in and the accounts were merged. Merging of accounts causes all sorts of issues like one of the parents was also a teacher so his student had access to edit and view all of his father's classes/grades/student information. Another student was repeatedly getting information sent to her intended for her older sister as the mother was observing her. There is not a simple process for un-merging the accounts either, it has to be done through an API.
When I asked support how to make sure this doesn't continue to happen, the response was "when a parent is setting up their account, you need to make sure that their student is not logged in, and not to have their student's login when doing so."
In a large K-12 district, I do not assist each parent with setting up their account and would like to be able to prevent this from happening. I would like the ability to turn off the ability to users to merge their own accounts in this way. We set up their accounts and there is really no reason that they need to merge them with another account.