I didn't notice the wireframe demo for the project creation process addressing this. There, the interface still provides a means to specify the investigator(s), with nothing implying to the user the distinctions between "attach this investigator to this project" and "attach an XNAT user to this project". I.e., the tag and user concepts remain conflatable because they're both "people".
Does anyone have any thoughts on how to make the distinction clear? Perhaps a fixed text notice and/or a stark (perhaps adjacent) widget for adding *users* to the project?
Hopefully a means of editing things like the investigator list are also forthcoming in the new interface...