"Search by name" actually searches by email address
If I ask to add a user to a project, and do "search by name", it seems to search by email (or by all user fields?) rather than only by name.
This means, for example, I can enter "qmul" to see all users with a qmul email address.
That isn't very desirable behaviour, and it also means you get an awful lot of results for many searches. The number of displayed results should probably be truncated (with some indication that this is happening) and search by email disabled.