Had little league game 13-14 with temp fence up and gap in foul territory. Runner on 1st no outs. Batter rips fair ball down 3rd base line. Ball goes foul and thru gap. All pregame meeting in TB umps tell me to have fielder throw hands up and dbl is given if fielder chases ball then it stays live and everyone proceeds at own risk. In this game the fielder went well beyond fence and as she was reaching to pick ball up she evidently remembered to throw her hands up. Ump called time awareded batter second and made the other runner come back to 3rd. I spoke to ump between innings and he said that was ground rule double. I asked if she was beyond fence when she threw hands up and he agreeded that she was and said it was still grd rule dbl. I then asked if she had chased it to 270 ft sign then and decided to throw her hands up would he still rule the same. I saw the wheels turning and he said he would chk with the league. I think/thought once she went beyond fence then it would stay live ball.