I didn't say it was a good solution. It is a solution. I thought you were saying that there was no current solution, which baffled me a little.
And you don't have to share your credit card information with all of the people in the household (although I'm not sure about B&N). When you make a purchase, enter the credit card info. After the purchase, delete the credit card info. Apply a little common sense and you should do fine.
FWIW, I wish there wasn't any DRM.