I could see a big company that sells all things hort giving a warranty on plants... if it dies or doesn't grow, give the customer a replacement and a one-on-one instructional about ferts, pesticides, whatever whatever, and they walk away with their free plant and $40 worth of supplies they didn't know they needed.
For a big box store, it may be worth their while to warranty plants that they KNOW are going to die, just to drag the customer back to the shop for their free replacement.
Foot traffic is key to the sales, bottom line the real hurdle is getting customer in the store. What are the chances you'll only pick up your warranty plant and not buy two or three " may as well get while I'm here".