It looks like a while back, the decision was made to convert tabs to spaces in code text (reference). However, today I encountered a problem in a white-space significant language where the user had mixed tabs and spaces inadvertently.
Pasting the user's snippet into my editor, everything worked just fine because the tabs had been converted to spaces. The problem was easy enough to track down, but that's not the issue. To me, it doesn't seem right that SO automatically changes the code that was input. Does anyone else have thoughts on this issue?