That stretch of canal is narrow and poorly marked. It's no surprise that people wander all over the place. Also... Hackney, and the east end isn't exactly the nicest part of London either.

> The point is, that heterogeneous users in crowded transit paths don't work well together

Which is a good point - most if not all "cycle paths" in the UK are shared with pedestrians who pay exactly zero attention to the red tarmac (for bikes) and the grey tarmac for them.