Actually nobody besides those monkeys, the people in Skypiea and now Foxy knows that Robin is in the Straw Hat Crew also it would be natural for Foxy not to know her, after all the marines doesn't know she is on Luffy crew so even if people see her they won't recognize her because the Bounty shows her has a Kid and was given 20 years ago, however when the marines discover that she is on Luffy crew i think they will issue a new Bounty with the updated picture perhaps 1 more million(So she can reach 80 Million mark GO Robin
) and announce that she is a member of the crew.