I've just been bitten by this, and I agree the language in the docs is very inappropriate (made me angry for a minute :)). 

One suggestion: "While not everyone might believe tabs should mean that, doctests are primarily aimed at documentation, and, since it's very hard to get tabs to look consistent, keeping hard tabs would be potentially confusing. If you absolutely need to test for the presence of tabs at the output, you can capture it and use string comparison, or write your own DocTestParser class."