My 2016 VW has a convenient button on the
lower section of the B pillar trim to switch off the interior motion sensors for the alarm if you need to leave the family dog in the car for short periods of time. VW have since deleted this button, and the facility to switch off the motion sensor in current VW’s is now buried in a sub menu, accessed via the infotainment screen. The Leon is the same - deactivation is by a menu setting accessed via the infotainment screen.
What could be easier than pressing a button on the B pillar to deactivate the interior motion sensor though? But it no doubt costs more to have a button to switch this function off, so we’re forced to navigate menus to do the same thing because it’s cheaper for VAG, even though IMO it’s much less intuitive for the customer.