Recently I pulled out my drive sensor-blocked PS2 slim to play some PS1 games via the swap trick at OSD (for anyone wondering, get yourself the GameShark PSone bonus archive disc. It offers a maxed-out ToC and will boot any game that doesn't require redbook audio). While I was swapping, I started to think about how the later model original PS and PSone models all had dual checks implemented to look for the SCEx code on the disc to help better protect against swaps at boot time. Why didn't they include (or bother improving) this check in the PS2? Surely Sony realized (with the slims, especially) people would block the sensors to gain access to some form of swapping. Why wouldn't they have beefed up that security? I've always been curious on this.