I wired in today before work, quite a simple job. I ended up using a switched fuse from the rear wiper.
Partly as you say the constant drain can't be good, along with the stop start system and alarm etc.
And also the dashcam didnt have a switched connection too, so I was dubious of its ability to know when it is in parking mode. Hmmmmm
I can always rig up a battery pack and run another wire up so if I'm parked up I can just switch over the and use the battery pack, and have that charge from the car instead.
Or its easy enough to find a constant on fuse.