Ok, so that isn't the only way you can lose a vending sites.
1. Put paper bags on your machine (if you are selling loose lollies)
2. Replace problematic product(s) (better to remove a product from your machine, no matter how well it sells, then to lose the vending machine location altogether)
3. Always clean up any mess you see from product sold in your vending machine
4. Give the manager a bag of coins (say $5 worth) for customers who need change and for those customers who lose money in your vending machine.
5. Test your vending machine over and over and over again for possible coin jams, products jams and equipment failure. You must become your own customer and see what if feels like to be ‘ripped off’ by the vending machine. If you don’t test and find out these problems in the comfort of your own garage, then I’m sure that the manager or customers you meet on your vending run will definitely tell you!