In Colorado the refs were fairly judicious with the penalties. The most common penalty was teams forgetting to get out of the end zone during the endgame. No yellow flags, but since most of the matches were fairly low scoring those penalties tended to sway the game. Even though at our regional the game was mostly defensive, not many of the teams had enough mass on their robots to really do a lot of damage to each other. The most damage I saw was from teams going up ramps or lifts and falling off.
There was a fun bit where we were partnered with team 1375 who had a ramp, and team 1977 who's arm had bent/broken early in the day, they were playing exclusively defensive with their omni drive

, surprisingly they did quite well at getting in between opponents and the rack. Since they had omni, they couldn't climb the ramp, but we really needed that 30 point bonus so our team agreed to try and push them up.
Last 20 seconds of the game, 1375 deploys the ramp, they line up at the base, we come up behind, we tap them, the crowd cheers, they go, up, they go up... and then we push them a little too hard to the side and they slam almost upside down, straight into the carpet, their omni wheels in the air spinning wildly.
We felt really bad about it, but they thought it was really funny, joked about perhaps we might have bent their arm back the other way so it might start working again. All ends well I guess
The big robot on the regional winning alliance (1583), which was basically just a box frame with a GIANT extra tall/long diamond plate ramp, they did very well at defensive, probibly the most aggressive team on the field, many robots got quite a beating from them, but it was all good because they were so gracious about helping them repair the damage afterwards.
Colorado Regional is always a treat.
-Chris