Presumably, Regina kept Belle as a hostage in FTL (episode 12) before she made a deal with Rumpelstiltskin about the dark curse (episode 2). She didn’t realize that he would keep his memories of FTL when he came to SB. So, she thought the “please clause” would pretty much be null and void. Regina wasn’t banking on Rumpel actually remembering his FTL identity or that he’d be able to get whatever he wants just by saying the magic word “please.” That is Mr. Gold’s trump card. I think that if Mr. Gold ever finds out that Regina has Belle in SB, he could very well use the please clause. He would have to be very careful in his wording to specify that Regina hand over Belle unharmed and alive. Another possibility is that Mr. Gold could call upon Emma to retrieve Belle as the favor that she owes him.
Very good and interesting points. 😀 I also think that Mr. Gold’s favor from Emma will have something to do with Belle. Well, either Belle or Baelfire. 😀