The battery and charger inputs have fuses. A short circuit will blow the fuse. Also, laptops and notebooks run on lithium batteries and have complex monitoring of power consumption from the battery. This is easily achieved with a shunt resistor (a low value series resistor that is used to measure current) which is hooked into the battery management circuit.
It is pure marketing hype to include a mention of short circuit protection. Short circuit protection is something that most electronic devices should have. If it has a lithium battery it SHOULD have short circuit protection because they can put out sufficient current to cause fires.
The battery will be shut of if there is either high current or the battery has dropped down to the cutoff voltage. Lithium batteries are damaged if the votalge drops below a certain level.
If you pour water into the device is won't necessarily shut off the battery because it won't detect an abnormal level of current consumption.