This week returned to PTY from MDE. We purchased Basic Economy. I am a silver member from my credit card. Flying to Mde I was told upgrades only are only for regular economy. I thought basic economy if available. Anyways did not bother asking at Mde. Get to the gate and my wife and I are handed new boarding passes which I knew was a good thing. Our friends already boarded and were upgraded to business class as well. Either it was because of my status on its own or economy was overbooked and we were upgraded because of that in addition to my status. I never walked into economy to see if it was full.