For example, in the US (and sort of in the EU) the FDA mandates that the responsibility of ensuring safety lies squarly on the medical device manufacturer. You are fully responsible for ensuring each part you select in the design process meets the requirements. So let's say a certain 8051 contains a major hardware bug that results in it failing to startup after the 2,000th reset. If you (as the medical device manufacturer) called out that the device would work for a duration of xx days, then you better have tested it (and documented it) under worst case scenerio. This essentially shields your typical semiconductor company (and others) from having any responsibility.

South america's will generally accept the device's use if the FDA approved. Asia's regulatory rules are a completly different ballgame though.

Bruce