As a measurer in British Columbia I find this very disappointing. There are a number of well qualified measures in the Vancouver area who would not have made this mistake.
The calibration course they referred to is probably one I set in 2004 which was referenced to fire hydrants at both ends, but as Ron pointed out those references are there only help you locate the pins. Also, an experienced measurer would have noticed right away that the calibration constant was not correct. Like most measures I inflate my tires before each measurement (usually the night before) and my constant is fairly constant and in fact I use this as a check to ensure I haven't screwed up in some way.
I did a quick check of the certified course list and I cannot find a certification for the Whistler Half Marathon or any other race in Whistler. If race directors don't use experienced measures and the measurer doesn't get the measurement certified it is not surprising that mistakes like this happen. Not surprising, but it is disappointing that this still happens after all the work that has gone on over the last 20 years to ensure that race courses are accurate.