I can confirm that enhanced summon is now in Ontario, Canada.
I just noticed the enhanced summon button in my app today. That could be because I just haven't tried summon for a few days, or it could be because I just logged out and then back into my app last night. (I was hoping to see the new window controls that some folks now have in their apps.) In any case, finding that enhanced summon is now available in Canada was an unexpected surprise.
I have tested the enhanced summon three times today, and it worked each time. The more barriers that I put between our Model 3 and myself, the more the car paused. At one point, it came unexpectedly close to another car that was parked between me and the Tesla, so I took my finger off the kill switch, and the car stopped immediately. I went around to take a closer look, and I saw that the Model 3 wasn't as close to the parked car as I thought, but it still gave me a bit of a fright. Nonetheless, there was lots of space in the parking lot, so I didn't think it was necessary for the Model 3 to drive so close to the only parked car that stood between me and the Tesla.
I also noticed that when I tested the enhanced summon from the greatest distance, I lost connection with the car twice, and I had to reconnect.
It was fun to test it out in parking lots that had no cars moving around in them, but I would hesitate to try it out where other cars are moving around... mostly out of fear of delaying and annoying the drivers of the other cars.