It's not a health and safety issue, it's a cheap approach to liability issue. Say that someone either hits Nick or pushes him into the canal causing an injury, any attempt at a compensation claim could be shot down by saying they have comprehensive training on how to remove themselves from any situation with an aggressive member of the public and that clearly this wasn't followed.
I've seen stuff like this for years as a way of dealing with the hyperactive litigation for any reason crap that spread here from America.
