Homophonic errors

The Salt Lake Tribune today carried the weekly Readers' Advocate column.  Someone wrote in complaining about the editors who missed two different homophones in separate articles.  One article was about the "sheering" off of a bus's roof (rather than "shearing"), and the other was about "towing the line" (rather than toeing).  I admit I was ashamed that I hadn't caught the errors.  I guess I am guilty of not paying enough attention.  I think that is why lots of people make careless mistakes in writing as well as speaking.  I just thought I wasn't part of "lots of people."  I've got to do better; I might be slipping.