The "Mass Login" watcher would indeed list plenty of other accounts as it takes a list of all failed logins across all accounts. You can limit the amount of what you call "false positives" by making it so that it only triggers on the same IP Address, as opposed to Any IP Address
I'll leave it up to my business partner Iain to explain why we rely on constructive criticism from our users in order to improve our mods, as I'm clearly doing an inadequate job of it
Fillip