Please, everyone, regardless of your company's SOPs, if the aircraft has power, APU, GPU, or in the case of GA, battery 'ON', leave the Nav/Pos lights on.
It let's everyone know the aircraft is powered, it could be under maintenance, things could move, be cautious.
There are numerous ground ops that require power on and its handy for all of them to look out of the office window and know they don't need to call an engineer or ground handler to get power on for cleaning, catering, refuelling etc.
Also, and this is a personal bug bear, last flight of the day, you guys are off home/hotel whatever after hard days flying. The rest of us have a job to do and on the Airbus in particular, one of those tasks is checking that both Nav light systems work. So that's two walk rounds. It's really annoying when you're half way round the post flight inspection and someone switches the lights off!
Thanking you all in advance. 👍