TL;DR: If you're doubling up in a parking spot, plug cash in the meter! Do not assume one bike's pay-by-phone will pay for both bikes! It doesn't!!
I'm not a fan of the park-between-two-spaces technique, I figure you are asking to get tickted, towed, or knocked over by some moron in car that can't parallel park. So I always park in a real spot. If you use the Verrus Pay by Phone app, you can park in any car spot and receive a 50% discount (). This is awesome when there is no MC spot around, and I assume the reason that it's 50% off is supposed to be that another bike can come along and park in the same spot too. This is obviously how it's supposed to work with motorcycle only parking spots downtown, where you often see 5 or 6 bikes crammed in there, and there's also no time limit... If you're lucky there's already time on the meter and you can just throw in a loonie or toonie and "do your part" for everyone's parking time. All is right with the world.
BUT, sometimes you roll up to that meter and there's no time on it, yet some pirate's expensive 30k harley is parked badly taking up most of the spot. So you figure, why not just jam my bike in there, that pirate surely paid for parking because he's not going to want that custom monstrosity towed... so you jam your bike in and just leave it. Always worked for me.
What also always worked for me was doubling up me and the girl's bikes in a single spot. We would roll up to any car spot, put both bikes in the spot, pay by phone for 50% off parking on one bike, and go eat or whatever. Never a problem.....
Then last week I was downtown for a meeting at the fairmont. No bike parking room so I pulled up into a car spot, which ad one of the aforementioned badly parked custom harleys in it. No time showing on the meter but I know the meter guys are aggro right there and street parking is super expensive. So I pay-by-phoned my bike in, just to be on the safe side. About halfway through my meeting I look up and there's a parking guy printing out a ticket in front of the two bikes. I vaulted the railing to make sure he wasn't ticketing my bike, but no, it was the harley, and he said straight up "this vehicle did not pay for parking" (which he can see when looking up the pay by phone).
So.. let that be a warning to those of you doubling up. You can still do it, but you gotta pay cash (that way they can't know (or prove in court) which bike hasn't paid). You don't get the 50% off rate paying cash at a car spot meter, so you are going to want to scope out bike parking spots. And even if there are a bunch of bikes there, if there is no money in the meter, use cash! Even if you're solo, help prevent anyone else parking there from getting a ticket. And if you double up in an existing car spot that you think has payment on it.. pay again anyway, it's 50% off by pay-by-phone.
Hopefully this info saves someone else a ticket!