Long time ago, I would occasionally get a package for someone named Carlos with my same last name. We lived in the same town, but otherwise our addresses were not at all similar. I opened the first one I got, thinking they'd misspelled my name. Felt guilty about that afterward, but that's what made me realize it wasn't for me. I called him up to come get his stuff. Never thought to do otherwise. He was very good natured about it.
I ordered a toiletry bag from Zulily a while back. I got a box containing one package with four separate bags. I could understand how whoever was packing the shipping box (if it was human or robot) would just think it was one thing. Those, I kept. Too much of a hassle to return them and what would they do at the other end? Prolly pitch them. So I kept one and gave one to my granddaughter, and the others to friends. If they'd come from a brick and mortar in town, I would have returned them. But Zulily? Nah.