In the end it's always a Regulatory issue depending on the regulations of the country where the device is sold. I'm sure there are countries where regulations are very lax, but those will tend to be countries where the market is tiny, so most reputable manufacturers will avoid them.

I guess what I'm trying to get at is that I think these Open Source Hardware/Software medical device projects are great. I really do. However people need to understand why they can't be considered the equivalent of a device that's built following the necessary regulations so they can make informed decisions about how they can be used.