My laptop woke up inside my backpack and arrived hot

I put my laptop to sleep, slid it into my backpack, and drove twenty minutes to a client site. When I opened the bag, the laptop was hot and the battery had dropped by almost half.

The machine had apparently woken while enclosed. I could hear the fan after unzipping the bag, but I did not know how long it had been running or what triggered it. An update, a connected accessory, a scheduled task, or an unreliable sleep state could all fit the limited evidence.

I shut it down and let it cool in an open space before using it again. I did not put it in a refrigerator, balance it on an ice pack, or keep charging it inside the bag. The case was not swollen and there was no unusual smell, but I am not treating one uneventful restart as proof that repeated heat is harmless.

My next test will happen on a desk, not in a backpack. I will record the battery level, disconnect accessories, close the lid, wait, and check whether the machine wakes. I also want to review its wake history and current power settings before changing them. Until I understand the pattern, I will shut it down fully before travel.

The frustrating part is that sleep is supposed to be the convenient option. A laptop that sometimes resumes in an enclosed bag turns convenience into a safety and reliability question.

What would you inspect first after a laptop wakes during transport? Which signs would move this from settings troubleshooting to “stop using it and get the hardware checked”?