Yeah it is such a waste of time and money. We recently picked up a client that has us testing 100% of their payroll checks, at various locations throughout the state, each month. We suggested just doing a sample, but no they want 100%. Which means they're paying us to send someone to Juneau once a month, as well as various places in town.
Thank god the people who make general auditing standards took a stats class and realize that testing 100% of things doesn't pass the cost/benefit test.