a battery installed the proper way will not short if there is not an atty on the connector to complete the circuit.
BUT if the battery is installed the wrong way, you run the risk off setting off a damaged (unknown to the user) battery if the button is accidentally pressed. even if there is no atty installed.
some people remove the atty or slightly unscrew it, when pocketed to prevent any accidental firing.
but in a direct short, that battery will heat up REALLY fast, and if the precise is in a bag, you will not notice it, and will end up with battery acid everywhere.
If the mod is designed a certain way, it should be used as such.
the only circuit protection in a mechanical mod is common
sense.