[TRWSHSHLX]

There's a lot of ways to play defense in a match. Some are perfectly legal but some not so much. From last year's experience (Oregon's first qualifier is at the end of January so I haven't really see much actually matches this year), here are some things that might help to understand why teams play defense and whether it's legal or not:

Acceptable defense: (all from what I had witnessed in an actual match before and didn't get penalized)
1. Pushing
2. Pinning for 5 seconds and back away 18 in. (one carpet length would be perfect because it's definitely longer than 18 in, I am not sure if it's two feet or 18 in. but same principle apply)
3. Blocking (Blocking as in preventing one direction of movement of the oppose alliance's robot, not ALL direction)
Defense that will most likely get penalized:
1. excessive ramming (it's pretty obvious and that's the easiest way for judges to DQ you)
2. flipping oppose alliances' robot over (sometimes it's not intentional but the referees will most likely think so. So if a robot and your robot is pushing against each other and the opponent's robot is climbing up the front of your robot, you should back off because if they keep driving straight, the judges will probably think it's intentional)
3. Intentional Entanglement (Reaching / Grabbing other robots hands / parts etc...)
There are probably more things for both lists but that's all I remember for now.

Most teams play defense it's because it's simply easier. It takes way less effort to play defense than playing offense especially when you don't have an efficient scoring mechanism. However, I personally think that ramming and intentionally ramming and breaking other robots is extremely unGP because if the situation is reversed and your robot is the one that's being rammed into, it's not exactly a good feeling. However, good defense strategy should be encouraged to some extend because that's when the judges can differentiate how efficient the robot's drivetrain and scoring mechanisms are compare to other robots. In World's final last year, the Smoking Mirrors shoot all their preloads in merely few seconds (literaly... 2-3 secs) and I don't remember how many they actually made but that showed how efficient their robot was. And for the last 1 minute there was a lot of defense played by both sides but the alliance with better drivetrain and better scoring mechanism wins.

As for the referees, there's nothing you can really do about it after they make a call. So the best thing to do is ask the possible situations that might happen and ask them how they will call / interpret it before the match. Another way is to follow what other people do. If one team's robot played excessive defense and it was allowed then it's perfectly fine to replicate what they do because they didn't call it the first time. And the same principle applies for whatever judges DQed people for.

Defense should be avoided if possible, considering how efficient the scoring mechanism work. In qualifiers it's not a good thing because ranking points will be very low; however, in elimination rounds, the point differential is what matter after all.

Good luck to all the teams out there!
P.S. If I have time I will see if I can post Oregon's last year's state final and there were some excellent examples of defense and good referee calls.