The reason for the redirect is probably so that they can change the URL without reprinting the menus. For example, if a small business changes who they get to do their online ordering system, sometimes that involves a URL change because coordinating the transfer of control of domain registration, DNS (and consequently sometimes email) and website hosting, and preserving the old URLs (or even just the entry point) on the new system is too difficult.
I don't think the lack of redirects would really resolve anything either. You either trust that the QR code you're scanning was really generated by the organisation you think it was, or you don't. If you trust them then you can also trust their redirects.
I don't think the lack of redirects would really resolve anything either. You either trust that the QR code you're scanning was really generated by the organisation you think it was, or you don't. If you trust them then you can also trust their redirects.