Key words "if they had the inclination." Imprinting minds with the idea that ideas should be tested by experiment is of tremendous value. Rigor can follow once the inclination is there.
Agreed, absolutely. You have to motivate rigor. I actually think the show does a fine job of that.
Sometimes they'll do a half-assed experiment, bust some myth, and then get viewer mail criticizing their technique. Then they'll revisit the myth, with better controls! This is pretty much exactly how real science works. Nobody does rigorous science because they want to spend enormous amounts of time and money doing the same boring experiment over and over, gradually imposing tighter and tighter controls on everything. They do it because otherwise their half-assed papers will get rejected by their extremely critical peers.
Sure, but convincing yourself of the validity of your own theories is always easier than it should be. That's human nature.
Among other things, rigor costs money and time. People's self-criticism tends to taper off as the deadline looms. This is a particularly important factor in Mythbusters -- my impression is that the Mythbusters folks are exactly as self-critical as their budget allows them to be.
