With the overwhelming influx of more and more bad quality code from beginners in tags such as PHP, jQuery, mysql, etc. it becomes increasingly likely that bad code / bad practice is not corrected which means that SO ultimately becomes a distributor/multiplicator of bad code / bad practice which would of course be the opposite of what SO is meant to be.
Some will now tell me that the community should just edit such code. But that becomes increasingly impossible for many questions. Because if you refactor the whole question, the question will become invalid.
I propose a way of marking questions or code snippets with obvious bad practice as such so other beginners can clearly see what is code worth copying/reusing/learning from and what is not.
I think it would be a great improvement for everyone, if it was clear whether a snippet of code is a good example of coding or a bad example.
Edit: In general I agree with Chris' answer but I strongly assume that Chris, not being active in any of the tags I mentioned, does not understand the scope of the problem we're facing in the PHP/mysql tag world.