A stray dog spent 7 hours at the sett last night, trying to get down the main entrance at one point. Fortunately he was too big (dachshunds or "badger hounds" are bred to go down badger setts).
I was not happy this happened so soon after the fence was removed (we're hoping the badgers will stay), but it's probably no harm for them to know that the world can be a dangerous place. Badgers avoid conflict whenever they can. Either or both could have seen off the dog easily enough but they chose to stay in.