I live in Southern California, so your "too close" is probably our normal. Having said that, if someone here is following too close, that means they are NASCAR style drafting (maybe even rubbing bumpers).
I'm always checking mirrors, so if I see someone coming up and I can get over, I do. If I can't get over and they are being real assholes, doing the NASCAR drafting, maybe getting onto the shoulder, etc., yes I will tap the brakes. I won't slam on the brakes, but I will let them see my brake lights so they back off. Then I will get over when I get the chance.
In heavy traffic in SoCal, if you leave one car length between you and the car in front of you, someone will pull in there. Stupidest drivers I've ever seen.