Why would anyone ever want a mattress permanently that was possibly used for sex by other people countless times?
Unless we're talking about "impure" from a moralistic pov. In which case I'd recommend slipping your local priest a few bucks to have it blessed.
If it grossed me out I'd rather not sleep on it at all.
I know the above happens with sheets. It isn't a stretch to believe it happens with other things as well.
The idea of using a mattress a couple times and then moving it to another hotel is laughable, much less for a "month". They easily last 5 years, if not longer, and it's a huge capital expense when they need to be replaced as it's usually done all at once since it disrupts operations quite a bit.