I noticed this for the first time last night after a cave exploration and I was trying to sell items that I looted that were NOT stolen, but I was over my carry weight, so I put the items in a chest for my pack mule to carry out. I got to the merchant to sell said items and took them from my follower and noticed that they were not in my inventory. I have been playing TES games for years, so I realized that they must be flagged as stolen. I took the items home and placed them in my storage chest, then checked the items and saw that, indeed, they were marked as stolen.
My question, if anyone can answer, is why is this? This forces me to sell said items to a fence instead of a regular merchant. I am a member of the Thieves Guild, but what if I had not joined or wanted to be a member. A matter of principal, if you will. Why are the items marked as stolen, when they are clearly not stolen?



Granted this isn't an ideal method if you have a lot of "stolen" items, but maybe it's better than nothing?