It's very easy to find yourself over the weight limit with all the stuff you need to fit in the robot and the weight of the materials you need to make it this battle-tough.

You can ask on /r/battlebots how many robots are skirting the fine line of the weight limit. Most of the builders on the show are actually on there and will happily answer any questions if you don't believe me. They're super approachable when it comes to this stuff.

Funny, /u/teamtestbot is a builder and he already found this thread and replied to one of the other comments in this chain.

Anything, thinking logically, these guys are some of the top minds in engineering. Why would you not attempt to get as close as possible to get the maximum destructive potential for your robot? If you're competing to win, why would you settle for less?