Infant fares are similar to Senior Fares: a discount off the Anytime Fare. As such, it is refundable.

Non-refundable WGA fares, if available, may be cheaper than Senior (or Infant) Fares but have restrictions -- including being locked to the infant's name if the flight is not taken (must cancel at least 10 minutes before departure).

If WGA fares are not available for the flight desired, Senior (or Infant) Fares will be less than the Anytime Fare and, as noted above, do have the benefit of being refundable.