The very nature of a wiki is that we want to work together. That does not preclude asking permission to edit a profile, especially those that are open. If major changes need to happen, absolutely, we should be talking to each other, using the bulletin board and G2G. But to just improve a profile-add more sources, update a biography, add categories and templates, asking first isn't really necessary. Often people are happy to have someone come along and add things. I know I can't get to all of my profiles as much as I'd like, so if someone else who has an interest can, I am happy to oblige. These are *our* profiles, not *my* profiles.
If the profile manager already has information that is not in the profile yet, this just gives them the opportunity to add it, or maybe the other person is going about adding it for them from their own research, and I do not see how that is a bad thing. Using the space to say what you're changing when editing the profile is always nice, too, just the other manager knows what you're doing. And, if something just isn't right, the changes tab records everything, so it is easy to restore previous information. I do not see how that isn't courteous or collaborative.