TFR Busts On The Increase

And the Darwin Candidate who was intercepted at the exclusion zone over the big G-7 palavar in Kananakis Country west of Calgary AB - a prime target for suicidal terrorists.

Intercepting CF-18 had to use flares and more to get the idiot’s attention.
Forced the airplane to land at an airport south of Calgary that was clear of zones, to have a chat with police.

(‘more’ wasn’t detailed in media articles I read.)

With Iran angry at POTUS Trump, and a history in the US and Canada of persons committing violent acts in the name of Allah.

(A sample case: Upgrade to charge against man with al-Qaida ties as punishment for alleged terrorism - Victoria Times Colonist
Several cases in Canada a few years ago of young males turned by preachers in mosques in Canada, some of them born in Canada.
And of older people in the US.)

There are ways to defend against UAVs, including taking control of them and either returning to launch point or at least getting data from them.

Trained eagles were messy. (Yes, someone in Scandinavia tried that.)

RCAF uses flares and something more dramatic it hasn’t revealed, in the case of a fool heading into the exclusion zone for the big G-7 palaver west of Calgary AB.
Forced the pilot to land at an airport outside the exclusion zones in the region, for police to ‘have words’ with the pilot.