[paavohtl]

Thanks for reading!

It's an interesting anecdote, but from my understanding of the system that simply shouldn't be possible. Your house's interior cell isn't loaded into memory when you are outside in Megaton, so there's no way for the NPC to access your items. I think this fundamental limitation holds true for every version of the engine, from Morrowind to Starfield, but I'd be glad to be proven wrong with concrete evidence.

[jwrallie]

Sometimes NPCs can follow you if they are close to the door when you enter, so while it’s not so common it could happen.