I don't know. I can only speculate it operates in terms of time passed/time remaining (miliseconds or whatever) plus an "expired" tag which, unless removed online, definitely says something cannot be played any more.
Interesting. What does it use?
It won't work. It doesn't use the system date to calculate how much time on your PS+ sub you have remaining.
Speaking of which, here's a question. If my PS+ sub expires, what happens if I try to play one of my PS+ free games offline with an old system date set?
Edited by dominalien at 11:46:23 25-06-2013