@Alligator:
My wife told me that we have those bread bag clips here in Europe, too.

While I understand the basic idea to have something simple to fint the way back to the trail, I don't like the idea to use something cheap and tiny. It may not be a far shot that it might happen another hiker used the same thing and left one behind, so you might be misguided. What leaves to the other concern, something cheap and tiny might all-too-easily be just left behind.
What about using your tent stakes, hanging two or three from the branches on your way off the trail?
This would be easier to spot on the way back due to their size, and you sure will collect them no matter what.