Satiated Vending Machines

Ever had a vending machine eat your money and then be unable to get it back, all because the stupid candy bar didn't fall down into the grab rack? You've tried shaking, and nothing has come out. Or it just ate your money and nothing happened? I propose a vending machine that measures the change in weight on the racks where the foods are, so that money can only be accepted if there is a measured reduction in weight and the food item has dropped into the bottom of the vending machine. If nothing happens, you press a button and get your money back. Of course, to make up for this technology, the prices would be slightly higher...

You could also ease the stuff selection process by providing a set of thick, long gloves that a person can reach through, similar to the ones used in clean room laboratory machinery, and thus reach into the machine and grab items without having access to the inside of the machine. The gloves are covered by a door until money is inserted into the machine. If the gloves are cut, an alarm sounds. The item(s) is dropped, measured and weighed, and charged to you as needed, but you can't claim the item until you have provided enough money to pay for the items. This wouldn't work for every type of vending machine, but might help.

This could also be used for electronic bulk vending machines- enter the number of pounds you want into the keypad and pay accordingly. For all of these methods, you can only be charged for a measured reduction in weight on the racks.