I have heard that in the states and Canada firms use it all the time
Cant comment on Canada, but in the US, in my experience, it is rare to need to add Prist from a can. Most fuel suppliers either sell only fuel pre-blended with Prist, or have an injector system on the fuel truck that adds Prist as the acft is fueled. If one is fueling out in the boonies, say from drums, might be a different story.