Morning, afternoon, evening everyone.
I also have a skin on my Mavic (from Decal Girl). It's Multi-Cam, I would rather not ruin my skin by either writing on it with a sharpie or sticking on any label that has a high potential to tear the skin if it is removed. I like the idea of writing on all of the props. Even writing on both sides of all of the props. My contact info in the battery compartment works, lots of area to work with. I also write on on all of my batteries too. How I am looking at the FAA's request/demand, to make sure that you get you ID number on you aircraft makes some sense.
In the even of a crash, you getting your bird back would be great, but no one getting hurt is far better. Just me thoughts here....