Chark on 18 March 2012
I believe that each account is allowed to have consoles activated with it, so if you can sign in with your son's psn ID you should already have it activated, if not look through the account settings for activation. If a "sub" account is different then a regular account I'm not too sure. If your talking just a profile on your ps3 well then it's really the psn ID that matters, so either have your son make one or continue using yours, unless you maxed out your activation allotment. If you are using the same ID, the download list is tied to the ID and not a profile on the ps3.
Before the PS3 everyone was nice to me :(
