Not sure how many of you have engineering degrees, but considering the minimal weight of a DP Dual LNB, I think that memo is more a precaution than a notice of manufacturing flaw. For instance, if the side brackets didn't have those little braces inside, I'd be nervous. Looking at it, though, I honestlly can't see how that bracket is built in a way that would make it vulnerable to wear and tear. Tip: Animals, Children, etc. are probably not appropriate to hang from the dish as a testing method; however, LNB's probably are, given that it's designed for that. The memo is probably more in regards to Dish Network realizing that the technicians tend more toward carelessness with delicate equipment. Then again, I haven't worked with a 500+/1000+ yet so I can't say for certain.
As for the LNB's overheating, you may have noticed a nationwide heat wave this year with even Chicago getting into the 100s. Considering people in Arizona have subscribed and continue to subscribe to Dish's service for years, I would doubt that the heat-sensitivity you're referring to is as widespread as you're making it sound.