Replying to Ski patrol told me I cant ski in the trees????

SO yesterday at keystone my friends and I decided to go catch a few runs in the trees because they've gotten some decent snow the past few days and we've been killing to get some powder underneath our skis. We entered the trees at the top of the trees right below the lift, mind there weren't any ropes our signs that indicated the run being closed. I knew the run was closed a ways down because of bare spots so we exited the trees onto the groomer which according to the ski patrol that came up to us after we came out was closed because it was after 3. I never really keep track of time when Im skiing because im having too much fun but apparently the run was closed for grooming. The ski patrol said he'd clip our passes but he didnt cause he said that we looked like reasonable guys and we told him it'd never happen again. The question that I have though is how can ski patrol clip passed for something like this. Pretty stupid in my opinion because by no means did they try and close the trees that we entered at the top of the run. It was pure coincidence that we came out of the trees onto a closed run. Mind I didn't duck any ropes what so ever.