I was observing a stronghold this morning and the bots bashed the Leviathan to death.

There was no player intervention.

I'm pretty sure this happens because the guardians aren't happy with their current salary compared to their work duties. also, some of the Ornes have been heard saying that they do the same work as all other guardians, yet they get less nanites to play with.

seriously though, ramming is a big problem. last night I rammed a leviathan by mistake (honest!) and it had maybe 5% left and died. I don't want to think how much the other bots do to it.