Furniture Store Acting as a MSB

One of my business customers owns a furniture store. In order for them to collect payments from many of their customers, they cash payroll checks. As the BSA Officer, I find this to be check cashing and asked them to register as a MSB. My reasoning is that more than likely the majority of their tax return checks or payroll checks are not going to the payment, but to the payees pocket. Do you agree with this?