We agree that you shouldn’t have to pay for the materials you’re teaching! Our system notes that you're a TA or instructor and marks your account as non-billable (it also removes the Opt-Out button).
You don't see the Opt-Out button as a professor, but your students will see it at the bottom of the screen when they click the RedShelf tool in your LMS.
If you get an email warning that you’ll be billed unless you opt-out, you can ignore it. You receive those emails as part of the class-wide notification. If you end up with a charge on your account, please let us know and we’ll take care of it!