Given the difference between the red and blue flags, here is my thought:
Capture the flag begins with red alliance's "flag" (likely a large bright light that can change between red & blue) already lit. Midfield is broken up by a significant barrier (like 2010) such that you could use only cameras to see once on the other side.
If ALL three blue alliance robots position themselves around the "flag", the "flag" turns to blue and the blue alliance gets X super mega awesome points. The red alliance must defend against them while also manipulating a game piece at midfield.
Game is over when the red alliance moves all game pieces to the center, the blue flag is lit, or 2:15 is over.
STRRRROOOOOOONNNNNNNNGGGGGGGGGHHHHHHHOOOOOOOLLLLLL LLDDDDD!!!1!1!1!!!111!1!