If you know that there’s no repercussion that you fear and your only goal is to take a picture, flash photography might not be the best, but still get the job done.
It also could be a means just to gauge a response for other knowledge
Nobody using flash photography for secret spywork is remaining a secret spy for long. Same for drones. I spend up to 16 hours a day (8 for work, 8 for gossip because people do be doing the wild shit) listening to various police agencies in my area. There are a LOT of restricted air spaces here, to the point where having a drone hobby is useless if you aren't an easy drive to the outskirts. I have heard a lot of drones getting tracked straight back to their pilot, sometimes before they even head back to their pilot.
Drones are such a terrible espionage tool that I am loathe to even consider that option for these
repeated drone flights. Sure, it's an option. But it's an option that gets you caught rapidly, especially if you are gambling repeated flights. If this is spywork, it's very stupid spywork that will get the spy burned and imprisoned all for information that can be gotten off Google.
The joke is that James Bond is the worst secret agent ever because everyone knows who he is. Every drone pilot trying repeatedly to be sneaky is a much less capable James Bond that will inevitably be caught.
On a semi-related tangent, there is presently much wailing that Ukraine/Russia are showing that drones rule the battlefield now. This is a faulty conclusion. They're barely out of WWI in that war because nobody controls the air, so that is a unique situation where drones can shine. The US has F-35s that can detect drone control signals to their source, so anyone trying to rain hell on US forces with F-35s in the air is going to eat a lot of high velocity metal.
There's a lowgrade drone scare going on right now and I do not think it is the drones we need to worry about.