I think it should be the opposite. Why? Everybody that has a different tab size will see text that is screwed up in the case of mixed tabs/spaces. Still in the 21st century there is a lot of files using tabs and spaces mixed together and still everybody prefers a different meaning of a tab in terms of spaces. This looks awful and the only way out it not using tabs from my point of view.
Well, "tab" and "4 spaces" are not the same thing, actually tab has no "meaning in terms of spaces" at all. The meaning of a tab is "indent one level". This may
visually appear to be the same as 4 or 8 spaces, or it may look like 5.35 spaces, or any other possible value. In any case, it does not have any such meaning.
Quite bluntly said, you want to forfeit the semantically correct thing in all your sources even though you know it's wrong because there are some people on this planet who are too stupid to do it right in
their sources. That doesn't seem like a good solution to me
But well, I guess it depends on what you do and what/who you have to work with.
It is just my belief that supporting wrong behaviour is not going to change it, not in the 21st and not in the 22nd century.
Can explain?
If you create a source file under Windows and later edit it under Linux (and maybe under Windows again), you will have a source file of which some lines have CRLF and some have LF. Similar problems occur with Mac.
This doesn't matter a lot for you at first sight, since there is no visual difference in the editor. However, under some conditions, the results may be undesirable -- most notably, Subversion will fail to accept your file if you try to commit it.
If "consistent line endings" is turned on, the editor will make sure all endings are the same. If they are the same anyway, nothing is done, so there is no harm.