the primary requirement for an exit node that no one tells you about:

balls of steel.

Has anyone ever been arrested or held legally liable for running an exit node (in a modern country, like the US/CA/UK/Etc)?

I've thought about running one as well since my server provider is okay with it as long as I handle the abuse complaints which is basically copy/pasting a cookie cutter response on how it's an exit-node and not possible to tell the origin of whatever it is the complaint is about.