Just a word of caution, while running a non-exit node is obviously safer from a legal point of view, the entire list of active tor nodes isn’t secret, and there are enough people in the world that do not understand how tor works that the chance is non-zero that you’ll still end up on a block list somewhere for simply being a “tor node”, even though you never let any of the tor traffic out on the Internet.

I know for a fact this can happen because it happened to me.