If you are giving them the inventory management software for free, that is a huge hook for cash strapped small businesses. And once your 'trojan horse' is installed, it's a lot easier to convince a small business owner to 'activate' the product sharing feature to gain an edge over other nearby businesses.

And then as you said, once one business does it, the others follow so that they don't become disadvantaged.

It would seem to me that the key to success is ensuring that your inventory management software is highly intuitive and easy to use for the time-poor business owners.