They goof off however they do it in a safe manner. I watched where they shot a bunch of stuff from a .410 that shouldn't have been shot. .454 casul, 44 magnum, .45lc etc. All done remotely for safety, and was more of a test of what can this old cracked stock .410 take.
Of course people don't understand metallurgy and my knowledge is limited. A gun rated for a max pressure of 45,000 might take 55,000 once, twice...100 times. However eventually something is going to fail. The danger comes that somebody might safely test fire a .454 casul in their .410 a few times as they do in their video, and then go "Oh it's safe!" the next day on the range, it blows up in their face.