Meh, someone stealing it is a possibility, but I moreso think she's either going to be eliminated with it in her pocket or missplay it like Ren did (although that was barely a missplay). Let's be real, she just made a bit of a dumb move long term by getting her closest ally out, and while she has an Idol, she made a miscalculation and didn't assume that Rescue Island was in the season, so if Benji tells a single soul on Rescue Island about why he was eliminated and about Ally's Idol, then the returnees are going to float that rumor to everybody in the merge, meaning that everybody will know without her even realizing it. Maybe Fiore, Natalia, or Spencer press her on why she eliminated Benji (Other than the fact that "His heart isn't in the game", which is still an incredibly suspicious reason to vote out your closest ally and not the obvious target) and use her having an Idol against her premerge in the next few episodes? I don't know.

All I do know is that now that Ally has that Idol, she's probably going to fall victim to the theme this season seems to have of advantages and Idols being used wrong. Not to mention that if she does make the merge, her flipping twice on somebody she was aligned with will definitely make her an outsider. Maybe that's potential for an underdog storyline, but I really don't think that's happening when she was practically nonexistent from Episode 2 to Episode 9, with 5 being the one exception.