Cayenne 2017 Boot Power socket

[Gc450]

Thinking of installing a rear view camera (dash cam) in the GTS on the tailgate and wondered if anyone knows if the power socket in the boot is timed to switch off. A quick test showed me it was still on/live with the vehicle locked but I haven't had the chance to do a longer test. I know in the past with other makes these sockets are on a timed system or respond to a current draw but unsure on the Cayenne.
Any help /pointers welcome
Cheers
G