Am I being "rude" for wanting to charge no-show deposits? My uncle thinks I'm ruining our family business.

Hi! I’ve been helping out at my family’s practice, and I’m in a massive disagreement with my uncle (the owner). Last month we had 13 no-shows. That’s roughly 25% of our slots. We’re still paying full rent and overhead, but basically working for free 1 out of every 4 hours. It's killing our margins. I proposed a simple fix: A deposit system where people put some skin in the game when they book. My uncle’s response? 'How can I say this to my customers? It’s too rude. You don't understand business.' He thinks being 'nice' is a better strategy than being profitable. Since I'm a CS student, I actually spent my nights building a basic automated booking flow to test this. My logic is that if a system handles the deposit and the 'bad cop' work of enforcing the rules, the client won't feel like my uncle is being rude—they'll just see it as the standard process. I even included automatic reminder and simple tracker to show him exactly how much revenue we're bleeding in black and white, hoping that seeing the data will change his mind. Has anyone here successfully moved to a deposit model in a small town/relationship-based business? Did it actually 'scare people away' like my uncle thinks, or did it just filter out the people who don't respect your time? I'm trying to gather some real-world stories to show him that its safe to implement than to lose money and time.