Rites of Passage in a new time

My daughter, watching me do some banking on line, put two and two together and figured out that if she has a debit card that she can earn reward points toward an iPod.  Being the persistent being that she is, she emailed her father (out of the country on a week trip to Australia) right away and inspired her brother to do the same.  He, of course, figured out how to make a video of himself to send in the email as well.
My husband said, "Yes.  With rules Mommy and I will talk about."  That was it.  Game over.  Get the cards in the mail.
We have opted for the pre-paid cards and will deposit money onto them for their allowance.  I am now going a little wild thinking of all the things I can have them "pay" for with these cards.  Haircuts, clothes, shoes, Starbucks for Mommy...hmm...
Then the almost five year old pipes up, "What do IIIIII get?"  Umm...nothing dear.  Because you aren't old enough.  But are the other two really old enough either?  It certainly doesn't seem that way sometimes but since I didn't have a gag reaction when my daughter asked or when my son persisted in his video to Dad email I suppose they are ready for this huge step forward in their journey towards independence and adulthood.
Sigh.
Here's a thought.  Do merchants really allow young kids to make purchases with credit cards / debit cards without their parents present?  I suppose we will find out.