[Steve Howland]

I don't think it will really be a problem in most cases:

Assume your robot is programmed to begin looking for green as soon as the match starts. To avoid robots running into one another, the bot looking for the tetra (decided upon by the alliance) would probably be in the "B" position (the one a little forward). It would somehow do a sweep of the field looking for green in a few quick seconds, and once it saw something green it would move towards it. For an ally to be the target, it would have to race out and get in the way of the green-sensing robot before it found either vision tetra. For an opponent to be the target, it would need to race across the field and be noticed by the robot before either tetra was seen, which would be pretty tough and clearly the only reason to do that would be interference, which the judges would notice and then penalize the team.