On my rare visits to the Doxey Marshes Nature Reserve at Stafford, the same two herons seem to be at the same places every time. This one is yards from the main path running more or less parallel to the River Sow, and never seems disturbed. A large group of walkers pass it: no reaction. Someone passes by having ignored the notices and let their dog off the lead: again no reaction.
The bird is near the path. But it is separated by a ditch which is just too wide to jump, and appears to be too deep to wade. If there were any real threats, it would have time to take off to safety.