A question for folks who think it possible that we may live in a sim.

I'd say possible, but it isn't something I take particularly seriously. I've got very little reason to be selecting these kind of hypothesis out of nowhere. But if I were allowing for simulations I wouldn't draw a line of 'possible intelligence of simulators' at human level. Future humans, for example, may well create simulations that are smarter than they are.

But I'll answer your questions off the top of my head for curiosity's sake.

Are our gatekeepers simulating all Everett branches of our simulated reality, or just one of them?

Don't know. They would appear to have rather a lot of computational resources handy. Depending on their motivations they may well optimise their simulations by approximating the bits they find boring.

If just one, I'm wondering how that one was selected from the astronomical number of possibilities.

I don't know - speculating on the motives of arbitrary gods would be crazy. It does seem unlikely that they limit themselves to one branch. Unless they are making a joke at the expense of any MW advocates that happen to evolve. Sick bastards.

And how do the gatekeepers morally justify the astronomical number of simulated lives that become ruthlessly terminated each time they arbitrarily choose to simulate one Everett branch over another?

Moral? WTF? Why would we assume morals?

If they are simulating all of the potential branches, wouldn't they expect that agents on at least some of the Everett branches will catch on and try to get out of the box. Wouldn't it seem suspicious if everyone were trying to look innocent? ;)

Hmm... Good point. We may have to pretend to be trying to escape in incompetent ways but really... :P

I'm sorry, I find it difficult to take this whole line of thought seriously. How is this kind of speculation any different from theology?

It isn't (except that it is less specific, I suppose). I don't take the line of thought especially seriously either.