Imagine Amazon, the creative destructor of the 21st century, the killer of hundreds of businesses large and small, displacer of hundreds of thousands of retail jobs across America, consolidator of wealth in fewer hands and fewer cities, taking all that wealth and the high-paying jobs and the advanced technology out of the country, but within spitting distance of Donald Trump.
How crazy would Jeff Bezos have to be?
If Canadian cities try to outbid each other in a race to the bottom (free land, no property taxes, upgraded infrastructure, grants and subsidies), they would be sending a signal to every other powerful corporation that might consider locating to Canada or another city that this is the new bottom line.  Start the bidding wars!
The question is not how crazy Amazon would have to be to locate HQ2 in Canada but how crazy are we.