I can't agree with you for one simple reason: I have never seen a file that exclusively uses tabs for indentation. There are always a few spaces accidentally t

I can't agree with you for one simple reason: I have never seen a file that exclusively uses tabs for indentation. There are always a few spaces accidentally thrown into the mix, and therefore, as you mentioned, the user has to know the tabwidth. Doesn't forcing the user to use your tabwidth defeat the whole purpose of using tabs?