@cferdinandi - You've gotten a couple other answers, but I figured I'd weight in.
1) Overthinking: My suggestion would be to see who is building and maintaining those other fridges and see if they have plans to expand out. Barring that, joining a local food group who is interested in building more fridges. Its good to join a group who can help you and you can help them. Really combats over thinking and helps you move into planning and executing.
2) Are you getting resistance right now? Or is it just a fear. If you aren't getting resistance yet, just do it and deal with resistance if it comes - dont stop because of a hypothetical. That said, these aren't meant to replace the food banks. Food banks are great. In our town, we work with the food banks. So whatever they don't distribute, we then move into the fridges. That way nothing goes bad. We also volunteer with food bank distributions. There is a lot of overlap between the two groups.
3) Joining food groups will help you learn what works and what doesn't. Don't worry about savior-complex - people are hungry, people need to eat. Heck, feel all savior-ey and complex-ey as you like... just feed people. Treat it like a project and do what works and drop what doesnt work.