Seven times in fifteen years?? I'd say thats remarkably low.
Of course its taught in Air Law but as the previous posters said, for many pilots that was several years ago.
I always try to give the benefit of the doubt - that they have not seen me and are not coming at me in some act of air rage!
Viz can often be poor, the haze this summer a good example. Pilots can be blinded looking into sun.
If in doubt you CAN shout - if you're using ATC. Unfortunately too many GA pilots don't.
Several weeks ago I listeened to a guy fly straight across a major airport zone and to ATC breaking off an inbound jet due to his actions. He obviously thought if you dont talk to them they don't know your there, an all too common attitude amongst a lot of private pilots.
Having said that, I think I've had a similar encounter with that jetranger..........