Where is the issue exactly? People can pay for their services. When a merchant sees, that people cheat on them, they will may search a solution. But is it probable, that merchants should be cheated oftenly? I doupt it. Like in every supermarket it is possible to steal things. But everyone knows that it is illegal and some percentage of stolen goods will be not discovered. This is not a problem for the supermarkets to sustain. Zero failure opportunity is not needed for an economy to work. It just should not fail too much.