I was try to bump an assassin out of the way by stepping on his square with troops. Having completely surrounded one, I then, whilst maintaing the circle, stepped another unit onto the assassin and he died. I guess it's the equivalent of flushing him out with a dragnet.

I don't think it's an exploit as it kind of makes sense - no need to lose your top general any more as long as he has enough troops to find and surround the assassin. I'm assuming this will work with Inquisitors too.

Thank God. This has saved the game for me on vh/vh. I previously lost my entire family, but one, to assassins and Inqs.