hmmm
I've never run into that. When play gets to me, I usually say (the first time around) "Do you allow surrender here?" (I already know that they do, but I ask just to appear less knowledgable.) I usually find the "Surrender is available" hidden in various places. I think the Beau Rivage has it on the podium in the pit IIRC, although in a few places I have seen a placard on the table.
Have you ever tried to surrender when the dealer gets to you and had him refuse saying "You have to surrender before first base takes a card..."??? If so I'll be on the lookout to avoid a potential mistake...