Ads-b != Ads-b
To make matters more complicated:
The US plans to adapt UAT ADS-B in the lower airspace and not 1090ES ADS-B.
The two are not compatible and could only exchange information through ground stations...
In fact the MITRE or any other UAT ADS-B unit would be illegal anywhere outside the US (as that frequency is used otherwise).
The survey does not apply for anyone flying outside the US.
And while we are at it: $200 in components translates to an end user price of at least $1200 and that's without certification, the user interface and GPS...
If you don't believe me: how much does a modern transponder cost in components? And what's the end user price? See?