It's certainly a common misconception. I certainly know that people in the "which bill do I pay this month" scenario often choose to hold off on paying Hydro during the winter. It's also quite likely that Hydro is less likely to disconnect during the Winter. Frozen water pipes can cause a lot of damage...
To be clear Ontario residents (really just in the GTA) refer to electricity as 'Hydro' because most(?) of it comes from the hydro-electric plant near Niagara Falls, and the company is called Toronto Hydro. Personally, whenever someone refers to the 'hydro bill' I have to internally connect the dots that it's not the water bill.
In this case, it's even less clear to those not in the know, because the next sentence refers to water pipes.
I used to work for the gas company (ATCO) in Alberta. It was an informal rule, but they wouldn't shut you off during the winter for an unpaid bill. I don't believe there was any law to compel them, but it's bad PR to destroy homes and potentially kill people over a few hundred dollars. They know you're ultimately going to have to pay the bill come summertime.
It's certainly a common misconception. I certainly know that people in the "which bill do I pay this month" scenario often choose to hold off on paying Hydro during the winter. It's also quite likely that Hydro is less likely to disconnect during the Winter. Frozen water pipes can cause a lot of damage...