Remember how the Highway Code defines a horn: 'A warning instrument'.
As such it is a useful addition to the tools we have to prevent an accident. Anyone who does not use one, almost as a matter of principle, is probably not riding as well as they could.
Evasive action and defensive riding are all very well, but a horn warns of danger, and potentially averts it, because the sound travels ahead of the motorcycle. It can be like someone riding ahead of you...
For instance, if used in advance of a turning or bend, it can cause a car about to pull out to halt. Much better than having to affect stability of the bike by swerving or braking...Which is not to say of course that it makes those skills redundant..
In the end, like most things in life, there is no simple answer, but I use my Stebel regularly and freely (as taught by the police rider who examined me for my IAM test).
There's also the argument that in waking up a dozy driver you make the road safer for the next biker. People are less likely to disregard something that can 'bite back'.
Not saying it should be used aggressively, but letting people know you have a (loud) voice is a good thing when you are a vulnerable two wheeler. 8-)
Just my 2 pennies worth... and only one opinion.
