Stopping can be tricky. I can remember way back when I had a 1700 lb popup. I didn't connect it up right (I was new at it then) and did not have trailer brakes. Good thing I was stopping at a little travelled intersection. I finally stopped in the middle of the intersection. White shorts turned an instant brown. From then on I doubled checked.
I have a hunch that trailer is way over 3000 lbs. I wonder if they are looking at 3000 per axle.
OP, what is the make, model and year. without knowing we are just guessing.
I did that on e 40+ years ago with a 1700 lb Apache pop up. The car was not set up for towing and I was in the process getting it ready. Just had the trans cooler put and had an appointment to wire it up for the trailer brake. I couldn't wait the extra week and took it out. Luckily it was a isolated 4 way stop. That trailer litterly almost pushed me into the intersection. Never made that mistake again.