Many of my students don't bother to use spell-checker, and it shows. Occasionally, I can tell that someone did use it, because some word they obviously didn't intend appears and was probably its suggestion for a word they spelled wrong but simply the wrong suggestion. In an exam I'm grading at the moment, a student says the following about Augustine's view of what takes place with the disordered state of our emotions at conversion:
"Conversion involves a reordering that starts in this life and explains how people become more vitreous."
This was from one of my best students, someone at the top of a class composed entirely of above-average students. She got a perfect score on this essay question, as it happens, and that's not easy in my classes. She just wasn't paying enough attention when her spell-checker suggested this for however she misspelled 'virtuous'. It's never good not to use spell-checker, but you have to be careful. Things like this happen, and misspellings that are real words never show up.