My wife just sent a link to the funniest entry I've ever seen on Ebay.  A mom with six kids recounts her story of going to the grocery store only to have the kids sneak Pokemon into the basket.  A sampling:

Shipping is FREE on this item.  Insurance is optional, but once I drop the package at the post office, it is no longer my responsibility.  For example, if my son decides to pour a bottle of glue into the envelope, or my daughter spills a glass of juice on the package, that's my responsibility and I will fully refund your money.  If, however, I take the envelope to the post office and a disgruntled mail carrier sets fire to it, a pack of wild dogs rip into it, or a mail sorting machine shreds it, it's out of my hands, so you may want to add insurance. 

If you're a parent, you'll understand.