Be very careful, I've even seen people from places like Microsoft showing code at conferences that would fail even a decent code review process.
I think for this reason conferences are a complete waste of time. Talks are too short to go into anything approaching useful detail, and s spend an hour talking about pointless demo quality code.. Or the talkers arent experts in what they are talking about. Waste of time.
I would say the same for the majority of blogs. Most are garbage and it can be difficult to tell the code is garbage if you're a beginner. I dont know a single development blog worth reading...