Seems like this would be easy to actually test instead of rely on a single anecdote. And the simplest explanation is a bug though I don't believe the story at all. There are probably multi-year-uptime bot servers in the wild right now.

Reminds me of when I was new to Quake 3 and found an amazing server: it was always full of players and full of non-stop action. I played with these people all the time after school. Nobody said anything, they were 100% business which was cool. I would often congratulate them on nice kills or commentate on my victories. Everyone was about the same skill level.

Eventually I realized I was playing on a server that simply filled empty slots with bots. I was the only human player.