I bought some used Hope Minis 5 years ago and never had a problem
You're in Ontario, where the temperature has been know to vary by 60 degrees from Winter to Summer, and you're telling me that your disc brakes worked all year round?
I don't believe it!
I have to say that I have ridden my Juicy 5 equipped Fuel throughout the year in Ontario, including in the last ever Uxbridge Icebreaker 50k (early April), Summer Epic 8 hour relays (30 in the shade) and the late October Hardwood Singletrack 50k, I've ridden it across from home to downtown and back in -15 temperatures (not counting wind chill) and never had any significant loss of braking performance. The 7" cleansweep rotors do go out of true at the slightest provocation though, and being the person I am, even the slightest "ching, ching, ching" drives me crazy.
1986 RM Ritchey "Canapurna", 1991 Marin Eldridge Grade, 1990? Vitus Futural CX, 1995 TREK Singletrack 950, 1996 Muddy Fox Monarch Team, 1997 DMR Trailstar, 1993 Pro-Flex 853, 2001 Santa Cruz Chameleon