It is a little unusual to allow a user to be part of more than one organization.

If you do this you need to carefully separate attributes that belong to the individual person from attributes that have to do with the relationship between a person in the organization. Often we treat the e-mail address as an ‘attribute of the user’ but I might very well want my mail related to organization A to go to my personal account while organization B goes to my organization B email account…. And worse than that it might not entirely be my decision to make.