A hibernating system won't wake up until you tell it to, which means you can count on your bag staying cool and your battery fully charged. On a PC running Windows 10, one simple solution is to change the behavior of the system so that closing the lid causes the system to hibernate instead of sleeping, saving the system's state to a hibernation file. You put the sleeping laptop into your travel bag and then hours later, discover that it woke up at some point and has been madly using up your battery (and heating up your bag) as it tries to do whatever task it woke up for. If you own a laptop, you might have experienced 'hot bag' syndrome.