SR is .onion you don't use exit nodes to get to it. The only way they could get you by running infrastructre is if they controlled enough entrance and internal nodes they could do a timing attack, especially with SMF telling the world when everybody is logged in but why bother, everybody just eventually drops dimes on themselves through massive opsec violations like this one guy who announced the tiny town he lived in and that "cops will never suspect my packages because the place is so small" /facepalm. He's probably the only Tor user for 100 miles