Are we allowed to block shots? I searched through the manual and found it nowhere. Thanks!
Sure you can block shots but you can only be 60" high on the defensive side of the court and the shooters can be 84".
Plus there are other rules to consider, like G28 and G44.
Essentially, there is no way to play defense in this years game. Since the offensive robots can be up to 84" high while defensive robots can only be up to 60" high, blocking shots is not really an option. In fact, if the defensive robot is pushed right up against the offensive robot and the defensive robot is the full 60", if the offensive robots shooter is a mere 36" off of the ground and shoots at an angle of about 70 degrees (which is a fairly plausible release angle, look at any basketball player shoot), there only needs to be 2’ of space between the edge of the shooter on the offensive robot and the defensive robot to clear it without being blocked. In addition to this, the key provides a nearly impossible to defend safe zone and the only way that you can effectively defend against a robot once it gets in the key would be to prevent it from acquiring any more balls past the 3 that it already had (assuming that it would have 3, I see no reason why it would not). Really the best strategy for defense would be to block robots from getting into the key in the first place similar to last years strategy of blocking robots from getting into their safe zone. By having a robot patrolling between the coopertition bridge and the opposing alliance bridge, it could force any robots from the other alliance towards the wall and pin to simply delay the scoring or if its drive train is particularly robust, then it could actually just keep pushing the opposing robots away from the key. In short, I believe that this year’s game will be entirely offensive with really no way to defend against a high class robot whatsoever.
This may seem totally useless but it is possible with the right camera integration and shooting physics to create a sort of ball defense system that could use something like controlled blasts of air to shoot the balls out of the air before they get into the hoop. you wouldn’t be able to be scored on and it would probably win you an engineering award 
I don’t know about useless, but I’d say more or less improbable (not impossible). While I would LOVE to see that happen, I don’t think a team will take the time or energy to do such a thing.
Unless you’re giving something away about your team… 
In the early planning stages, it’s easy to fall in love with scoring and hard to see the value in defense. However, I think it’s fair to say that more shots will be missed than made. If you develop a strong ball collector, you can rebound up to 3 balls from the floor, retreat to the alley, and send all 3 balls over to your partners. Such a bot would be valuable to a good alliance.
I know our team rejected the defensive strategy IMMEDIATELY because they found it unsuccessful last year. Apples and Oranges. Remember, “Offense sells tickets, but Defense wins Championships”. Heard that on ESPN somewhere. Good luck to all this year.
Why would it need to be a controlled blast of air? Wouldn’t a continuous blower do the trick? Perhaps vary the angle and speed slightly to make it difficult for shooters to compensate?
You may be interested in this thread, about air defense systems. It discusses the pros, cons, and overall feasibility of various types of air weapons.
well I dunno I just feel like a continuous blower would be problematic for your battery. It’s not as much fun to think of it as a defense system if it doesn’t single out targets