Activations made by a user that has not logged in with their Redgate ID or is using a very old tool version (prior to the launch of user account licensing) will be recorded as Not logged in in the customer portal.
This is also the case with server based tools. SQL Monitor and SQL Backup are licensed per server so it's not conducive to tie a server license to an individual user.
Owners and administrators of the license can remove the user to free up the activation for someone else. See Deactivating A License (Removing A User).