So, I have a confession to make.
I've never taken a bathrobe or towel, because (1) it is stealing; (2) it's not very classy.
However, some years back my wife & I were staying at the Hotel Zurich/Zurich Marriott (it changed names around that time).
The hotel has air conditioning and heat, but the windows could not be opened. My wife prefers an open window. Everytime we got back to the room, she would call down to the desk and ask that the windows be opened. About 10 minutes later, someone would come by with The Crank That Opened Windows.
We were staying a number of days, so this happened quite often. One time, The Crank was left behind (accidently).
My wife hid The Crank in her luggage, so it would be available when we needed it, and wouldn't have to call down.
We eventually left and flew back to the States. When we unpacked, we realized that we still had The Crank.
We considered sending it back, but we were hard-pressed to explain the whole thing. It is pretty heavy, so it might be expensive to ship. And I'm not sure how we would do the customs declaration.
So, we still have The Crank. Maybe I'll remember to take it back next time I'm in Zurich.