Also, they won't stand by the center if the D is not sending anyone out. In this case it should have been the FG D unit and it should have been out there already when the FG unit came out. It only comes into play when the O subs under 15 secs then it gets dicey.
"Late in the first half Team A is out of timeouts. A pass play on third down ends inbounds at the B-25 short of the line to gain with the game clock showing 0:10. Facing fourth down and three, Team A immediately hurries its field goal team onto the field. RULING: Team B should reasonably expect that Team A will attempt a field goal in this situation and should have its field-goal defense unit ready. The umpire will not stand over the ball, as there should be no issue of the defense being uncertain about the next play." Rule 3-5-2-IX