That's strange, in all the time I've spent on SO sites, I can remember only one instance where that happened. Maybe it's community related and happens with certain topics more than with others?

Happens a lot in questions related to C. Most answers are followed by a discussion why the code provided in the answer is not portable. Oftentimes answers are more concerned with being technically correct than helpful.

In the particular case of C, it's often important to be pretty precise. If an answer is offering a non-portable solution, or worse still, relying on undefined behaviour, it should get called out. It's not like, say, Java, where you're generally unlikely to get bitten by dark corners of the language.