Flashing blue is ONLY to be used by police or a snow plow that is under contract by the province or municipality.
Now there is nothing saying that a private snowplow can not have blue while in a parking lot....but forget and push snow across a road, back onto a road, or just drive down the street while the light is operational and it is an offence.
Easier to just go buy an orange lens to fit your current light and never have to worry about forgetting to turn it off..
Just an FYI...flashing blue has always been prohibited on private vehicles on a highway.
Above is merely a suggestion/thought and in no way constitutes legal advice or views of my employer. www.OHTA.ca