When you capture flag, the old flag goes down, a new flag goes up. pretty simple really. the flag stays at the top until there is a change. when a change occours, the old flag sinks into the ground and a new flag rises to take it's place after.
How about the closer you are to capture the flag, the higher your flag flies example: BE start capping a flag on escort; the NF flag slowly sinks down, after neutral phase is over the BE flag starts rising
the problem is that is that it's not obvious what state the flag is if it's near the bottom- if you can spawn or not. and more importantly, that that is EXACTLY what BF2142 has atm.