Sound signals
e) If you hear two blasts of a horn when a boat is coming toward you, they are trying to warn you of something.
...is both wrong and dangerous.
Regularly tugs a butty
As someone who regularly tugs a butty around, the use of two blasts is 'I intend to pass starboard to starboard (on your left)' or, more literally, 'I am altering course to port (left)' although I generally use it when the butty is pushed to the left by the wind and unable to easily pass on the right.
The sound signal for 'I am towing' is, according to the bye-laws;
Sound signals 12.(c) A vessel when towing and a vessel under way which is unable to get out of the way of an approaching vessel through being not under command or unable to manoeuvre as required by these Bye-laws shall sound, at intervals of not more than one minute, three blasts in succession, namely, one prolonged blast followed by two short blasts.
Cause accident
Although it is unlikely many people are educated enough to realise this, I still hold, strongly, that to subvert two blasts for her own use is likely to cause accidents and if in the case of such accident it is shown she caused that accident by giving the wrong signal, she will be at fault.
I feel strongly that we should stick to such regulations as are given and not make up our own.