iLugger fitting

I saw videos on how to put my 20in iMac into the case, and they put it in upside down. Is that bad for my Mac? Couldn't that mess it up?

Consider what you do to a laptop as you heft it around, pass it through airport xray machines and the like. Now consider that an iMac is basically the same idea, just packaged differently. I saw the video too - I don't think it will cause any harm.