There are several factors involved in decided whether or not the ramp is a valuable asset during your match.
First off, do you still have balls loaded to shoot?
Secondly lets once again look at the points involved.
-Each ball through the center goal scores 3 points.
-Each ball through the corner goal scores 1 point.
-1 robot on the ramp is 5 points
-2 robots on the ramp is 10 points
-3 robots is 25 points
-4 robots is 25 points (and a guaranteed of 15 ramp points denied to the opposing alliance)=40 possible points
-5 robots is 25 points (and a guaranteed of 20 ramp points denied to the opposing side)=45 possible points
-6 robots is 25 positive points (and a guaranteed of 25 points denied to the oppossing side)=50 possible points.
Now the defensive points dont mean anything if the 25 points you score don't give you the lead anyway, or the points they score outweigh the 25 points you score. And also obvioulsy size is a huge factor (the most robots I bet anyone will ever see on the ramp is 4, and that will be VERY rare).
The balls are a scoring resource that is replenished (the rate of replenishment is hinged upon your robot design and/or human player skill and the opponents willingness to re-introduce the balls into play). The ramp points are not, you get them once at the end of the match.
If you are down by more than 25 points, the ramp is not an effective option unless you're "throwing in the towel" and just going for RP (and if your down by a 40 point margin or something, or you are being completely denied balls to shoot, that may be a fully acceptable action to take).
Next, examine the actions of your opponent. If they have defensive positioning and are not allowing you to take accurate shots at the goal, why bother? Additionally, if you have defensive positioning, why sacrifice it?
Now, if you have defensive positioning, and they go for their ramp, why not go for yours and effectively nuetralize any offensive ramp points they score (provided your in the lead)?
My last point will be this -> TIME.
Assuming you travel @ 10 fps, and your shooting from in front of their ramp, there are 40 feet to travel before hitting the foot of your ramp. Factoring in getting up the ramp and acceleration it will should take rougly 6 or 7 seconds to get onto your ramp from that position un-obstructed.
If there are 2 other robots on your ramp, your robot would essentially be worth 15 points. That is 5 balls in the center goal. You have a little over a second to fire each ball to normalize the points (assuming you already have the 5 balls loaded and ready). This also means you CANNOT miss a shot.
In short, it's a situational decision that must be made on the fly at the end of the match. How much these situations will arise and the best way to deal with each of them, I will leave to your individual teams to decide (I have my own opinions that are well, my own
).