[edit]
For example -
ok :
Memory card 1 - Platy psn account with Uncharted and Kingdom hearts
Memory Card 2 - Platy psn account with Little deviant and Little big Planet
not ok :
Memory card 1 - Platy psn account with Little deviant and Andrefpvs Psn account with Little big Planet
[/edit]
Not exactly. The last scenario may be possible *if* resetting to factory defaults does not clear your card, but you'll need to reset to factory defaults when you switch account. Read Crystal's quote again in the Wired article.