If someone set up a Coke machine that stole people's dollars, do you think they'd notice? This doesn't have anything to do with the scam, but simply being completely oblivious as to what's going on in your place of business.
I don't think the people at the front desk are aware of which contracts for vending machines or ATMs. They could have had 4 guys bring it in and make up a slick story about how they had a work order to install the machine and the front desk would probably not have the authority to act in any direction other than send the info up the chain.
