yes if banned you can play offline. you cant play any online multiplayer games or what have you but those are a very small number or often even just a part of games. and this method will continue to work. it masks your console as another and allows you on though you do not need to spoof anything but your console ID so this guide is a bit dated. here is a simple guide that should suffice for any CFW user.
1. download the latest version of PSIDpatch for your CFW version (3.55, 4.21 etc) right now I believe it's 2.0
2. find a valid console ID thats not been banned yet. (figure this one out yourself I will not tell you where/how.
3. place your new console ID in a .txt file. again this shouldn't be too hard to figure out. and save the file as consoleid.txt and copy it to the root of your USB HDD or flash memory device.
4. run PSIDpatch and press L1 it should change your console ID top the ID in the text file. if it worked press triangle to exit the PSID patch app and you may now sign in.