our hounds are trained to show sign along the track, the germans call this verweisen and it is very good on difficult tracks that cover a long distance, I know 100% my dog is correct but people following often say your going the wrong way, but my dog then stops with her nose on the floor pointing to a spot of blood I show this then everyone then knows we are correct.
my dogs tail is straight up like a flag pole on track if she runs on she circles round and finds the point where she went wrong, she wont miss out she goes back to her last point then carries on. Here's a little video from when she was about 16 weeks old, learning to indicate and track, every training track is done to succeed we make it more difficult only when the dog gets it and nails it down we then move to the next stage before long you are doing 24 hour plus old tracks and with back tracks
and deer crossings, regards wayne