It's not quite "30 minutes or your pizza is free," but close: Between Thursday and March 31, 2015, Delta Air Lines will reward you with 2,500 frequent flier miles if your checked bag isn't on the luggage carousel within 20 minutes of your flight's arrival. 

According to the description of "Bags On Time," Delta writes on its website: 

We're committed to providing you with reliable and on-time baggage service every time you fly. That's why we're backing your bags with a guarantee: if your checked bag doesn't arrive at the carousel in 20 minutes or less after any domestic flight through March 31, 2015, you are eligible to receive 2,500 bonus miles. 

To take advantage of the offer, you must be a SkyMiles member at the time of travel and complete a form with your flight information online.  Just note, it can take up to two weeks for the comped miles to show up in your account. 

It's unclear what prompted Delta to run this promotion, but anything the airline can do to engender good will at a time when travelers are frustrated with its frequent-flier program changes can't hurt. Here's hoping Delta will make it a permanent offer.