In American usage, toward and regard are preferred. My sources say that towards is British usage and regards has some special uses - give my best regards to - but is not interchangeable. Both forms are used in casual writing, though.
I’ve never heard “ignorance to the law” and can’t imagine why anyone would think it’s correct.
I think the preference for toward in the United States goes back further than the AP’s edict. Every magazine I’ve copyedited at (all in the U.S.) has preferred toward, and most of them followed a style guide other than AP’s (Words Into Type or The Chicago Manual, neither of which comment on this issue). Also, most American dictionaries list toward as the preferred spelling.