The foundation may control the github repository of bitcoind/bitcoin-qt, however they do not control Bitcoin. If they have decided to give themselves 1 million coins or whatever, no one will use and people will fork in true open source fashion.
This is naive. Of course they would not do the obvious. But for a group of knowledgable persons it is easy to implement some "errors" that go unnoticed long enough to inflict serious damage.
Only a tiny fraction of all bitcoin users is able to understand the source code. And of this tiny fraction only few do actually verify it.
Wow. This is true paranoia. You really need to seek professional help.
The Bitcoin Foundation does not control bitcoin. It never will. Even if it manages to implement "errors" into the code, those errors will get noticed at some point because there are enough people outside of the Foundation that understand how bitcoin works and -- guess what? -- THEY WILL GO TO JAIL FOR CRIMINAL FRAUD. Because, as somebody else mentioned, they are a central organization and everybody knows who they are.