Originally Posted by mfFrom35K

This is to update this thread with new info on the fare rules. I have tried again today to book JetBlue fully refundable fares and the fare rules are updated and clearly indicated that there is no penalty and the fare is fully refundable to the original form of payment. The confirmation e-mail and manage booking screens now also indicate refundability. I am much more comfortable now booking fully refundable fares with JetBlue.

I would note that not all flights have the option. You do need to select BlueExtra to get the option but sometimes it is not available. The flights where I did not see the option were high demand dates such as the Sunday following Thanksgiving. So it appears JetBlue is unwilling to offer this option that is reasonably priced on flights they have high confidence of selling out. This makes sense from a business perspective.