A while back I signed up to rammy.site a small lemmy instance run by a single person. It was a very nice instance, very stable and had pretty good access to other instances, or at least it used to.
Recently though all of that has changed when the instance was taken over by far right-wing users from the right-wing instance known as exploding-heads, an instance which has been blocked by many others for the hateful content they post and the abusive behavior of its members. The reason that this was even allowed to happen was that the admin stopped moderating the server but left the server online, this is a problem because it means that anyone can hop onto the server and start posting whatever they want and create whatever communities they want and no-one can stop them.
There isn't much you can do to prevent going innactive but there are ways to mitigate what happened on rammy.site to prevent a full blown catastrophe like what has happened here. If you run a server and you are going to be going away for a while I'd recommend turning off account registration and community creation on your instance, that wouldn't prevent federated users and existing users from spamming existing communities but it would help against users joining the site and creating new communities which is what happened here on rammy.
I understand that it's not always possible to always be there to moderate your instance but you can at lease take steps to ensure that in your absence the instance won't be utterly decimated and/or used as a weapon to spread hatred or attack other instances.
I admin a small instance as well and I have only blocked lemmynsfw.com at this point. I like to keep the server open to all unless a rule is broken on my server. This means even if I don’t agree with what is be said, again, as long as it is within the rules of the site.
It baffles me as to why you would go through the trouble of creating an instance and just leave it to rot with no oversight.
Because moderating can be a full time job. If you go for a vacation, have a family emergency, etc and aren't actively looking at your instance, then it's "left to rot".
If it's possible, doing the steps OP mentioned before going on leave will help the server avoid getting into a mess while you're gone.
Kinda dislike this about selling stuff on Ebay, you've got to be always available to dispatch an item. They've got a "on vacation" mode, but if you forget to switch that on and someone orders something, you're SOL
It's better to have them forget about it and have the server and its communities locked than it is to have them left open to abuse in your absence. At least in the case of the locked one they can still use it on their communities on other instances (I see no reason to lock existing users, just registrations, community creation, and maybe posts and comments on hosted communities).