I've been selling cutting boards at craft fairs for a couple of years now ... two observations:
1. I will share ALL information about what I do and what my process is. I've had woodworkers ask me where to buy lumber, what glue I use ... I'm an open book. Woodworkers appreciate the information, and consumers like the stories I tell about how it all works. After all, if they're buying an heirloom quality cutting board or wooden serving piece, they want to know what they're buying. And since my boards are sometimes described by other people as pieces of art ... purchasers will want to know the artist behind the art. No. Secrets.
2. My wife sells small batch lotion products, and is constantly being asked about her ingredients, how natural the products are, etc. For a maker of cutting boards, keeping information secret about what products are used to prepare a food safe area is INSANE. Is it FDA approved? Avoiding such a question will cause sales to evaporate from any concerned consumer. Ignorant people may buy, of course, but smart people will not and ultimately, people are smart. That's how I treat every consumer. Don't you think?
I know some people use salad bowl finish on cutting boards, but I categorically reject any film-generating product, as that film will find its way into your food. Mineral oil and locally-harvested beeswax are all I put on my boards, and all that my purchasers are instructed to use.
After all, I expect their boards to last decades with proper care. Therefore, they need to know how to care for them in 50 years and beyond. Keeping a key component of routine maintenance secret? Laughable.