P2 Prospect2 - Changing Email Addresses Requires Access to Custom Tab - How are you managing access?

Hello - 
We've been using P2 for about a year now, and just were informed we have been handing email changes improperly. In order for the email change to be recognized in P2 it has to be changed in the P2 Custom Tab, not the Contact Details Tab. We have restricted many of our Tessitura users including Front Desk employees from accessing the P2 Custom Tab as you can change people's subscription preferences and mess up their accounts easily from that tab. However, it now looks like we'll have to give everyone access at all levels. 
Has anyone else in a large organization had to handle this? How did you manage access?

Thanks!
Jane Esterquest
Isabella Stewart Gardner Museum