Funny about the shoulder thing. I was stopped in traffic just yesterday when two guys on sport bikes decided to do the shoulder thing. They should have looked back first. The stoppage was due to long announced construction and the cops were there to make sure all rules were followed. Sure 'nuff...two cops on their Harleys pulled them both over. I don't know any place that driving on the shoulder is legal.
I have not seen any deliberate lane splitting in Orlando except for a few brain disabled riders going 30-40 faster than the traffic and they were more weaving than lane splitting.
It's so rare here that I can imagine a few drivers "accidentally" opening their doors in stopped traffic. If it were widespread and legal, it would probably be safe...or safer.
Jim