Redmine

We're authenticating our Redmine installation against an external system. Thanks for the great alternate authentication source mechanism--aside from a typing error in the class name, I got that going without difficulty.

However, on the external system members can have multiple accounts with the same e-mail address. My first thought was to just remove the uniqueness constraint from the user-model, but I was worried there'd be side-effects I can't anticipate. I read an issue where the problem is discussed to some degree (#688: http://www.redmine.org/issues/688), but came away from it unsure how I wanted to proceed.

I also came across #7599, http://www.redmine.org/issues/7599, which talks about using blah+something@somwhere.com format addresses. Gives me the idea that I could do something where my auth_source plugin automagically generates a +something variant--but that will only work for those members that have accounts at servers that understand that syntax.

Another option (but has its own problems) is tell the "reporters" they have to decide on a "primary account" to use for reporting (developers/managers already have this inherently). This is has some customer service drawbacks and is my least favorite option.

My main question is--what are the problems I'll cause if I remove the constraint? Issue 688 mentions problems with Lost Password and registration--those don't apply because they are handled elsewhere (by the external system). What are some of the other problems?