That's actually a neat policy: The Birthday Grace Period. :D The perfect allowance for sending things in the mail, and as you said, it prolongs the fun! :D

Me, worry about spoilers? Not for the Simpsons, by any means. :D Groening puts in so many little Easter eggs in his work that it would still be very enjoyable for me even if I knew beforehand that Lenny and Carl got married to each other, or something. ;) So spoil away! :D