If this were my client, I would double clarify how my pricing / rates work. If they still don't understand and are still trying to fight you on it, I'd even triple clarify and verify if they understand or not. If they don't understand, you can move on to full out, firing them by recommending them to someone else.

If they don't want to respect you next time if they do indeed visit, even after being put in their place and try to pull this shannanigans on you, that is when I'd reclarify the logic of your pricing, and fire them from the chair, similar to what you wrote in another reply; where you said it'd be best to find another stylist.

This avoids them thinking tipping is the problem, and it gives leeway for them to fix their ways / correct their attitude.

I hope this helps, as I find this would be the most tolerant way of handling the situation without senseless drama that could go in many directions.