Exactly this. You can end up with some weird situations. I saw one guy get a criminal conviction for this: he repaired elevators. He left RepairCorp where he worked and set up on his own. BuildingCorp continued to pay him for their repairs not realizing it wasn't RepairCorp. In the trial they stated that they were always very happy with his work and the price was identical to RepairCorp. They were pissed he had lied to them though, and the guy ended up getting convicted for fraud.