In time they get scratched by forks, while putting in the washing mashine, by anything and when they are scratched the inner aluminum comes into the open and that's no good. Contacting with food while cooking might transfer the scratched aluminum into the food. Aluminum is outright dangerous for any living body.
Sure, but this is why I dont use metal in those pans, why they always get hand washed, etc. Care for and respect your tools and they last practically forever.
Well it's not me, the other households handle those parts carelessly and the aluminum is easly dented, scratched. But the point is, such parts should be made of anything else, such as copper, suitable type of iron, anything but aluminum. Also, considered in terms of value a $20 toast machine does have aluminum pressing plates, too.
Additional source: I know a lawyer that worked for DuPont. Their job was ensuring that DuPont would never be held accountable for problems caused by Teflon. That was enough evidence for me to throw away all of my teflon pans.
[1]: Specifically, http://smile.amazon.com/Emeril-All-Clad-E83602-Anodized-8-In... (not an affiliate link)