Robb Allen points out that “something that happens” is not the same thing as “legal,” but I doubt it will make an impression on her; certain segments of the population talk past each other on many issues (not just gun rights) because of using words in different ways (Kevin talks on this a lot, but I can’t find the particular post I’m looking for right now).
The most striking example, I think, is the word fair; either a process can be fair, or the outcome can be ‘fair.’ If the outcome is ‘fair,’ then everyone gets the same thing no matter what they put in; if the process is fair, then it treats everyone the same. The rich are not proof that the system is unfair simply because they are rich when many are poor. The process itself isn’t as fair as it could be (mainly because of lobbying by businesses to create barriers to entry), but it could be far worse.
Meanings do change over time; literally now literally means figuratively (in spoken English, anyway). This isn’t the same thing, though; you can’t be Humpty Dumpty and make up your own damn meanings and expect people to go along with it (though you can make up your own words; Japete’s use of the word legal was not cromulent at all).