We had a supermod (someone who mods hundreds of subreddits) try this on a small subreddit I was active in years ago. They must have had a watchlist of subreddits to claim because literally the day the only mod's N months was up they posted to try to take it over.
It was a small sub and we were all well behaved so there wasn't really any need for moderation, and we didn't want some random outsider coming in and taking it over as part of his supermod powertrip or whatever. We organized against it and the Reddit admins ultimately denied the request.
I was so bitter about the experience that I wrote a script that crawled the top 10000 subreddits looking for possible takeovers, and my friend and I took over a few dozen lucrative subreddits*. Think generic words like r/skateboarding (not one of them). Just add a spammy automoderator account to your modlist so it can't get taken back over.
It goes by the "last activity" timestamp of your creator/modlist, so even if you are actively moderating your subreddit (like attending to the mod queue), your subreddit can still get taken over if you aren't posting.
The system is so, so stupid.
* If you search the takeover requests subreddit you could even see that we weren't even stealing the subreddit from the original owners who did all the work to grow the subreddit, but rather from other takeover bots.
It was a small sub and we were all well behaved so there wasn't really any need for moderation, and we didn't want some random outsider coming in and taking it over as part of his supermod powertrip or whatever. We organized against it and the Reddit admins ultimately denied the request.