I think Sam's also is still doing non-refundable resv... In Feb, I inadvertently booked one for two of my traveling group, and tried to undo it within minutes... argued with everyone under the sun for about a week that I didn't want to cancel, I wanted to switch to a refundable resv just in case we did need to cancel months later, and got nowhere...there was still plenty of availability at that point, but they wouldn't budge.
So before you push that BOOK button... be sure it's what you want as there is NO grace period after you book. Life is uncertain, and who knows if what you plan to do almost a year from now will still be doable.
Luckily, it looks like my group will not need to cancel... and we are still planning to go.