Everywhere I look these days I see the word "lose" being spelt "loose" - which as anyone with the vaguest grasp of spelling know means something entirely different!! What is happening to the English language..?!
FAQ, I think a lot of people do because of the pronunciation of loose/lose and choose/chose, and it's for this reason, shona, that it doesn't annoy me as much as they're/there/their,your/you're and its/it's. Unfortunately English doesn't have very consistent pronunciation rules unlike other languages (French and Dutch being two of them). It makes tutoring English difficult, I can tell you!
That said, I do agree with cattj that the English language (well at least spelling and grammar) has gone to hell in a hand-basket!