I use pants at all of my GORUCK events now. Previously I used shorts but quickly became tired of my knees getting cut up from low crawls on the ground. There’s a good chance that at some point you’ll be crawling over sand, dirt, rocks, or concrete and any of those can do a number on your knees.
Once I started wearing pants to these events everything changed… no more banged up, bloody, and cut knees. Because of this I recommend pants to everyone who attempts a GORUCK event. It should be noted that this is just my preference and I’d say 80% of people at these events wear shorts… but there are definitely a few who wear pants.