Hartmut,
Do you have kids? If I picked up my kid’s toys for them every time they left them laying around and just stuck a sticky note on them, they would never learn to clean up after themselves. They would, however, learn that other people’s messes are their problem which is exactly the opposite of what I want them to learn. Teaching someone that there are consequences for their actions (or lack of action in the case of not locking their workstation) is far better than being an enabler.