The NSA is intercepting shipments of routers, and installing their own... stuff in them. I don't know if the stuff is hardware or just software/firmware.
How would 'open source' protect you from this? If the 'stuff' is firmware, then reflashing your own firmware after you get the device would protect you from it, but it doesn't particularly matter if the firmware you flash is open source or not. If the 'stuff' is hardware, then only someone inspecting the insides who's qualified to detect such hardware would protect you, and it's still got not much to do with open source.
How would 'open source' protect you from this? If the 'stuff' is firmware, then reflashing your own firmware after you get the device would protect you from it, but it doesn't particularly matter if the firmware you flash is open source or not. If the 'stuff' is hardware, then only someone inspecting the insides who's qualified to detect such hardware would protect you, and it's still got not much to do with open source.