What about just plain old errors? I know someone - a good songcrafter and not illiterate who recorded 'the tempetuous sea', meaning, evidently, 'tempestuous'. And what about those who sing 'calvary' for 'cavalry'(and vice versa)?

And what about presentation? I have a friend who wrote a 5-verse song and varying chorus who sings it in a certain order because of the harmonies. But she's WRONG! She sings the last chorus, and invites the audience to sing along, as 'Did YOU do what you came to do'?- It's MUCH more effective singing 'Did I do what I came to do'?, etc. :)