Companies can have their machines calibrated for many different reasons and these need to be regarded separately from government inspections.
Some may have them calibrated to satisfy an auditory requirement of their quality program and the program dictates the frequency of the calibration visits.
Some companies may have high value product passing over their scale and so are conscious of the value of product giveaway.
There is also a requirement from Measurement Canada that a company must do all that it can to ensure that their legal for trade scale remains accurate and normally this is through regular maintenance and calibration. It may be wise to alter the pattern of calibration visits so as not to coincide with mandatory government inspections but the number and frequency of calibration visits is normally decided by customer.