There has been a remarkable diversity of comment, the majority of it well intended and good humoured - thank you.
I confess that I am disappointed to hear that there is, among a part of the USA populace, a sense of entitlement that causes them to become enraged and engage in anti-social behaviour when they see someone filtering/splitting.
In Australia, another country where this type of attitude does regrettably exist, it is really only the odd person here and there that will take aggressive action against the motorcyclist. Strange though it may seem, cagers tend to be more antsy against bicycles, as THERE is a body of folk in which the number of those who believe they have superior road rights compared to others is quite pronounced.
Still, when in Rome, do as the Romans do; so if and when I need to do something that is common sense but nevertheless illegal and/or frowned upon, I will do it with great caution.