The person you released was a syndicate who has been yelled about multiple times and I'm pretty sure even their name was said. You even saw them yourself as me (One of the Secoffs) and you were there at bridge. You the Warden are held up to higher standards and shouldn't be releasing people because "the release of that guy didn't hurt the fun from anyone in the server" when it allows them to freely get away and kill whoever along with completing their tasks. I believe it was also mentioned that the person had an emag. I'm not sure how you missed all of that, but I assume you weren't paying attention to the radio.
Even if you were never warned about using syndicate bags, it does not excuse anything. You should not use syndicate items at all, including bags. Sure, it doesn't sound that much of a problem, but it is what it is.