Currently Being ModeratedFeb 1, 2013 12:21 AM (in response to NeddySeagoon)
You can only subscribe to match via your computer. You should only use one ID on your computer as you risk being locked out for 90 days if you use different ID.
I have no direct experience of using multiple ID's, but if match is turned off, you can sign out of your iTunes account and person B can sign into his/her account.
I can't answer what happens to previously downloaded content once you go back into match on your ipad.