The electrician in the show that day explained a code violation regarding wires not twisted together before placing them under a wirenut. Although it is very good practice and I would not recommend doing it any other way it is NOT A VIOLATION. He used this as one of the reasons to rewire the 3rd floor of that house >>> clearly not a reason. He also sited live wires ending "free" without being in a junction box, violation no doubt but easily fixed by shutting power and terminating in a box. By the way >>>Wirenuts are designed to hold the recommended amount of wires without twisting them, again not my recommendation but legal.