I've just had one of these. The hotel I was in had poor housekeeping in general, but they were getting very passive aggressive about my towel use. I'm a woman, so I use two: one for my body, one for my hair. It was evident that I was using two and from my belongings that I was female.
I return to my room, find two towels taken away, only left with one. I go get more towels myself. The next day, both towels taken away, only one left for me.
Very unusual for me as I find housekeeping very efficient in general.