I've been doing it for 40 years, although I don't have occasion to do it very often these days. But when you are doing it regularly you get a sense from the drivers body language when they are going to change lanes. If you don't do it at insane speeds, it is safe enough. Its the cars traveling towards you or at right angles to you that are most likely to kill you.That is because you aren't supposed to do it in a dodge dart.
Splitting lanes is part of the deal out here. Just have to watch the kooks.