I successfully lane split in California for many years (Oakland/SF).
It's terribly handy in rush-hour traffic and at stop lights.
At a stop you filter up front - the cars are already stopped so less chance of getting rear ended.
When I lived in Chicago I lane split for a couplea years. Totally illegal, but I'm impatient.
A job I worked was up north. This particular highway had all the jerks.
(I never had this problem on other highways in Chicago-land)
I'd lane split on the way home through the stop-go traffic.
(completely stopped for periods of time. It was an awful commute.)
In the six months I was working there, I had at least four cars open their doors on me.
I had a semi try to run me off the road. Really. Out of it's way to try to squish me. That was fun.
If I hadn't been filtering slowly and carefully, I would have gotten injured by one of those doors
(as it was, they just got an ear full. So did the semi driver. Grr.).
Like all riding, you just gotta be extra aware of your surroundings.
And unlike my Chicago experience, I never had a driver open a car door on me in Oakland, SF, Vancouver B.C., or Austin Tx.
Like anything new, it'll take a little while for cars to get used to it.
It'll take bikes time to get used to it.
After a while, it'll just be the norm.