I've never even gone near Cabanas when staying Concierge. There's enough food in the lounge to hold me off until the crowds die down.
The biggest thing that frustrates me about Cabanas is that the majority of diners seem to be first-time
DCL cruisers, or first time on the Dream-class ships, so they don't understand the concept of station buffets, thinking it works like a standard buffet. They queue up just inside the door and give people nasty looks (sometimes even saying something to them) when others in the know move ahead of them to the next station. Eventually a Cast Member will come over and explain it to them, but for a while the line can block the entrance.