I know this post was specifically directed at out-stations, but don't try this at Heathrow! Or Newcastle. Short haul at T5 will frequently close up 19 minutes before departure. I was on a 767 bus departure out of A4 quite recently and passengers arriving at T-18 were denied boarding: they had closed up, the driver was getting into his seat and we were off a few seconds later. If you check the Newcastle departure times they are sometimes airborne 10 minutes before departure.... Every departure yesterday left Woolsington at least 5 minutes early. I've seen long haul lock up 30 minutes before departure.

But my own personal take on this is to get familiar with how airports work and work around it. So Vancouver's departure screens are certainly not to be relied on, for example, Miami and LAX T4 are semi automated (it needs intervention to change information otherwise it keeps to script). Generally you need to allow 20 to 30 minutes if you don't know the system.