Early A "Brake" Warning Light?

I towed a Mazda GLC from El Paso to California behind a U-Haul truck on one of those dollies they lift the front tires off the ground. I guess we had left the parking brake on. When I first drove off, I was thinking, "Wow, this truck is really loaded down, it's hardly moving from a stop". My best friend, who followed right behind me the entire trip, failed to mention he noticed a little smoke during the initial part of the journey. The rear brakes were toast when we arrived to our destination. We had left late one night and were exhausted after packing up all day long (this fatigue may have affected our thinking by the time we got ready to leave).

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