I have a friend who is a senior in college, and she says there were several people in her class who used to word "ain't" in one of their papers. I guess they critique other peoples papers and that is how she saw it. The teacher actually called them out on it too. I don't understand why adults who are supposedly educated still don't know how to read or write properly.

Schools tend to like to push kids along the systems in order to raise their test scores. They fudge on the marks so they can get more government funding. It's a horrible system.

Good question... I wonder the same thing.

As "aint's" been in the dictionary for a very long time now I don't think it's a good example of spelling/grammar issues.

I'd be more concerned with victims of the Internet age and their everyday use of ur, ne1 b4 and the like.