"I agree with Erik completely. Design and consideration of the parameters that go into the design are the only way to ensure that the resulting product will have a chance to demonstate its reliability!!"

Indeed, I would never advocate not designing something carefully.

"because you are not designing carefully if you do not ensure correctness at every step."

Indeed.

"I say only "nearly disagree" because I do admit it is possible to make a contraption that "works" correctly within its design parameters but may fail for other reasons outside of that set of parameters."

You can't expect something to necessarily work outside its design parameters. It wasn't designed to do that!

"For example, a vented brake rotor may work great from new through up to 0.030" of wear and resurfacing, but may be of dubious use after exposure to 10 Minnesota winters of salt covered metro freeways."

Indeed - it wasn't designed to withstand that exposure. Cars are not designed to withstand normal usage for any length of time. If they were, they'd be very expensive but you'd only ever have to buy one.

"Another example could be an aluminum grain shovel, which works wonderful in the grainery for shoveling oats, but used to shovel snow on a concrete driveway and the product fails miserably!!"

Again, you're using it for something it wasn't designed to do. Why would you expect it to work?

My point in this thread has been that sweeping statements are often inapropriate - in particular you can't necessarily say that something is unreliable unless it is demonstrated to be unreliable, and by the same token you can't necessarily say that something is reliable until it has been demonstrated to be reliable.