If you ask me, it's bullshit. Because first of all, it doesn't work, well it only works for a few people, most people say it doesn't work because it stops sometimes..., now second of all, it isn't even worth it, brick your PS3? For getting a MW2 Patch on your PS3 just to host Challenge Lobbies? No, it's not really worth it, and now the bad news, Sony will probably find a new way against the CFW user, so if you use a CFW on your PS3, and you update your PS3, you will probably get banned or something (not sure about that).
But still, a new 3.60 Firmware will be out soon, and I'm sure that a few people are working on a 3.56 CFW, so I wouldn't risk it to brick your PS3 for something you can do in the future anyways.