I did the Palo Be Our Chef experience for my 50th birthday in March 2019 and it was the most amazing experience. Yes it is $279 per person but you do get a chef's jacket, apron, hat, recipes and photos. Yes, the class is open for concierge guests to book first, and then if it is not full, it is open for other guests. I lucked out when I did my class because there was only 3 of us. I was Platinum, one was gold and one was her first cruise, so as Gold it is possible you might get to do this. An exception to the pre-booking rule was done for me as I was celebrating my 50th birthday so I cannot comment about booking onboard but do know that one of the ladies in my class said she went when she boarded and they told her if there was availability. One thing to be aware of, the class is either on Jamaica day or Tortola day (depending on if you are on an Eastern or Western cruise) and the class runs from 11 am to 1 pm.