does improper usage become proper when it's commonplace?

Traditional critics have insisted that nauseous is properly used only to mean "causing nausea" and that it is incorrect to use it to mean "affected with nausea," as in Roller coasters make me nauseous. In this example, nauseated is preferred by 72 percent of the Usage Panel. Curiously, though, 88 percent of the Panelists prefer using nauseating in the sentence The children looked a little green from too many candy apples and nauseating (not nauseous) rides. Since there is a lot of evidence to show that nauseous is widely used to mean "feeling sick," it appears that people use nauseous mainly in the sense in which it is considered incorrect. In its "correct" sense it is being supplanted by nauseating.

http://dictionary.reference.com/search?r=2&q=nauseous