Yes, you can misuse the harmonica. Common execution problems include:

• Having too many transitions. What does this mean? Some people give too many instructions in a row, and they use PAX Quiet to stop kids doing what they are doing many, many times to give new instructions.
• Failing to praise for quick responses to PAX Quiet.
• Rarely celebrating students’ success at the transitions of PAX Quiet with occasional Granny’s Wacky Prizes for “saving so much time.”
• Giving the verbal instruction for the next task without having the children’s eyes on your mouth.
• Getting emotional if they don’t respond.
• Failing to follow up when students are sloppy; it’s a good idea to respond: “Oh class, we weren’t so good with PAX Quiet this time, let’s try that again.”
• Turning away so that children cannot see your lips move when you give the follow-up instruction after PAX Quiet. Children are less likely to respond if they cannot see your lips move for the instruction. This is particularly true for children whose first language is not the language of the classroom.