http://web.archive.org/web/20191014214750/https://bitcointalk.org/index.php?topic=2564886.msg26125867

The terms of that bounty don't state that alt accounts are not allowed to be used.

A neutral tag would be appropriate and a warning not to merit the alt account (against the rules).

Symilar cases:
https://bitcointalk.org/index.php?topic=5147367.0
https://bitcointalk.org/index.php?topic=5048262.40