Students will often try to get away with the least amount of effort. This is a test of your compliance standards and needs to be addressed. The message should be, “What we do, we do right because it helps us on the path to a black belt.”
Excellence is the habit: what you do, you should do well, and the easiest way to do it well is to do it well every time. If the instructor has set raising hands as the expectation, he/she should stand by it.