NAND flash requires soldering through a JTAG or serial port, doesn't it?
This is pretty interesting, being a software hack that's more or less transparent to Sony.
The only method they'd have to catch that, until a further hw revision - that can check authorized components IDs, like the disc reader, is probably autoban all people involved if more than two connections from the same ID are detected.
In all likeness, a NAND copy through serial ports will override all IDs, so the only check possible is against components outside the main board. Disc readers generally haven't even got serial ports for flashing, so they're a good target i reckon.
Also, i don't think they're losing online connectivity, not until sony patches something to detect cloned IDs. It all depends on how they store HWIDs - if those are in the NAND, they're overridable.