Pressing the fob twice de-activates the ultra sonics inside and disables the deadlocks. One press is all thats required.
I have an '07 GTI and, according to the owners manual, pressing the fob twice deactivates the deadlocks and the
entire anti-theft alarm system.
Press fob once = Doors deadlocked + vehicle fully alarmed (i.e. No passengers left in vehicle).
Press fob twice = Doors locked, but not deadlocked +
no part of alarm system activated (i.e. Passengers left in vehicle).
Press button on drivers side B pillar + fob once = Doors deadlocked + vehicle doors alarmed, but interior and anti-tow sensors disabled (i.e. Pets in vehicle).
Basically, make sure that your car is fully deadlocked + alarmed when left empty or your insurer will not pay out if it gets nicked.
Hope this helps.