picker Instructions for assigning a bug are ambiguous

[Curtis Hovey]

The picker to assign a user or team to a bug task that you have no privileges for looks very similar to one that you do have privileges for. ie. I can search for anyone when assigning to projects I maintain/drive/supervise, but for other projects, I can assign myself or my team. The only difference between the pickers is the instruction text:
     "Select a team of which you are a member"

Though the text is correct, and there is a link to assign myself. the information/circumstances are not obviously different. Two experienced users stumbled on this issue. They could use the assign-me link, and they could search for their teams, but they did not know the rules for the bug target were different than those they commonly work with.