I will sometimes steer in to a lock and whilst the gates are being closed nip inside for the toilet or to get a drink. I certainly wouldn't expect to return to find paddles had been lifted. Also I tend to dislike revving the engine hard in reverse in a lock so if I stay on the boat I keep it at the back of the lock and expect the paddles to be lifted steadily to around half way to ensure the boat doesn't bounce off the gate and then surge forward requiring reverse. On most of the BCN, especially with single gates, paddles can be lifted straight up, the T&M it is certainly half way and one at a time.