I meant that's not a bad policy. I know the guys and so just trust them personally, but if you have no basis of them, their history, and what seems likely to you, then yeah that's a very prudent stance to have.

Same goes for all the software we use. In a very similar sense neither MacOS or Windows is open source. For Mac the kernel is open source because its based on Linux, but things like the user interface and graphics engine are closed source.