How rare is a wiring harness restraint failure on 2001 volkswagen Passat v6

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I have a 2001 volkswagen Passat with a V6 automatic with approximately 171000 miles. I had the timing belt and front oil seal replaced at a local mechanic. 4 months later, the wiring harness came loose from its restraints and got caught in the fan blade, broke and cut through the main radiator hose causing a catastrophic overheat and head damage. Is it true that the wiring harness must be detached from its restraints when removing the front of the car to access the timing belt and front oil seal? If the wiring harness restraint failure as I described is rare in the Passat, is it fair to assume that the wiring harness was not properly restrained when the car was put back together after the timing belt and oil seal replacement?