Here are some suggestions.
Please note! This is a mattress cover!
For hygienic reasons, it should always be covered with a bedsheet.
Since we respect your privacy, we kindly ask that you make the bed yourself.
Please use the folded sheets provided nearby.
Thank you for your cooperation!
This sentence is confusing -
Our housekeepers can’t fly (unfortunately) and they can make the bed
only if they are on it.