>>You can always WATCH them change the sheets if you want to. I have done that<<
Exactly. And if in doubt, flip everything back and look at the sheets. If you see anything suspicious, call the management and have not only the sheets but the bedpad changed.
Or find another hotel.
The management does not clean the rooms. They trust that those they hire do a good job. If that is not true, the management need to know it.
And I’m sure they would appreciate being informed as well. Businesses want and need to hold onto customers.