As for towels etc, I get my own off the cart 99% of the time if I need them.
And how do you think clean towels got on the cart, conveniently located just outside your room, in the first place? A housekeeper loaded her cart with towels and other supplies to serve "her" rooms, then pushed the fully loaded cart to "her" floor. By taking towels off the cart, you saved her only the last few steps. And then you stiff the tip. Wow, what a mensch. (not)