You did the right thing, I would have essentially done the same thing you did.Yesterday when I arrived at the pick up location the rider came out with sealed Box and he will not go and wants me to deliver this box to the drop off location. Since I don not know what is in the box so I refused. Price was surging at 1.4 that time. So I cancelled the trip and informed Uber and demanded a cancellation fees for my time. Uber guy replied it "you get cancellation fee if rider cancel after5 min or if you cancel after 5 min of arrival." But this scenario was different.
Btw my question is to you guys what would you have done? Would you just accept this trip and deliver the box? And is it allowed? The uber guy did not answer that part.