This Gold "benefit"
Enjoy free of charge preselection of your preferred Standard seats, for all Aegean and Olympic Air operated flights, any time you wish, for you and your travel companions, online or offline through the Aegean's Call Center
My booking had me and a non-Gold member under the same code, but online system gave me a glorious error. I tried the "gold members" line and worked then (although they were not sure why that did not work out). By the way (because I called from my M+B phone, they greeted me with my name).