Agreement/Checkbox on Checkout

So, I have a site where I sell soap and candles.  With the heat, I'm always afraid of things being delayed and melting when being stored.  

Is there a way to put in a 'checkbox' or something the customer has to acknowledge, that even though we use ice packs, their product may show up damaged from heat, and have them accept responsibility for the shipment before they place the order?

See Creating a custom checkout form.