In the scene where Sara arrives and Louise has to tape Ian, the tape almost touches his left side-burn while, when coming back to the house the tape now is far from it.
As anyone who has used duct tape will tell you, many times you use your teeth to tear it when you don't have the use of both hands. Both women could have easily freed themselves.
Ian asks Lou if the robber touched her, despite seeing him touch her.
When taped to the toilet, Ian says, "I could care less!". The expression is, "I couldn't care less."