Your site is a marketplace. What users need is trust in other users, not trust in your source code. What happens if someone loses your pricey lens? Or sells it

Your site is a marketplace. What users need is trust in other users, not trust in your source code. What happens if someone loses your pricey lens? Or sells it on ebay and disappears? Those are the main issues. Furthermore, you aren't in the open source business. What happens if someone offers you a patch, and it is not in the direction you want to go? What happens if someone is not satisfied with your service and forks the code base? Now you have even more problems.