The cars computer doesn't care if it's on a maintainer or not, it will shut down the alarm to conserve battery power. If your thinking that the voltage is being monitored by the computer and once it goes bellow a certain reading and shuts down is false. New battery's versus old battery's have different capacities and an old one will draw down faster giving only a day or two before disabling the alarm...if that was the case.
Porsche disables the alarm but your car is still protected because
after manually unlocking the door the alarm is
again activated and that's why it is a requirement to disable the alarm, with the fob, before opening the door. This insures you have the key in your possession and not a car thief going through the top to open the door.
P.S. I never lock mine, it stays locked up in my shop. Long term storage would worry me because of the thought of the key fob battery going dead.
