Im reading that it all depends on honest workers
what sort of business relies on the sole discretion of workers being honest - What happened to management? I always post up that running a business is more than book keeping and supervising - You should know all 60 minutes of at least the first 180 degrees to run your show, The rest 180 degrees can be had from experience.
If your workers are losing the money then either your workers know more than you about your business or you are not prepared (best be a silent investor only then).
e.g. in car repairs lets take umm (A/C evaporator removal in a car)
In average small/medium jap car it takes 2 hours to disassemble the dash and remove the evaporator - usual charge is Rs 4000/- (plus evap cost extra) for the whole job. Same job in a mercedes benz w211, 210, 124, 140, 201 - takes about 10 hours just to remove the dash to remove the evaporator.
An inexperienced person may sign up for Rs 4000/- and spend 4 days just working on one car. BAD PRACTICE.