Using QuickSale at bars/restaurants/in-house cafeterias

We're in the really early stages of investigating using Tess QuickSale at our cafe's and bars as well as our staff cafeteria and have come up with one possible hurdle that we are trying to figure out.

Our current system for the cafeteria is that a staff member can 'pay' for their items using their payroll number. Payroll then pulls a report from the cafeteria system every two weeks which totals up how much you have spent and that amount comes off your paycheque. 

We've run through a couple of ways of doing this with QuickSale

• changing customer numbers to match payroll numbers - not ideal and not very secure as anyone with access to Tessitura can get someone else's payroll number
• using the check field in the money bag to record the payroll number, however this does not provide a confirmation for the cafeteria staff of who that number belongs to so as to avoid a mis-type of the number
• creating an attribute (Cafeteria ID) with the value being the payroll number. Somehow having the constituent search screen default to this attribute so that the cafeteria staff can enter the payroll number and easily find the staff member - again not very secure unless we can control group everything so that only cafeteria staff can see this attribute. 

Is anyone out there in Tess-land doing something similar to this or have any thoughts on what you would do, presented with the same?