I think it's more than fair. But do people seriously think that housekeeping has the alloted time to do thorough room sweeps? I think the standard practice for hotels is around 20 minutes per room for each housekeeper. It's one of the reasons I hate the beds with a bunch of pillows on them (especially the decorative ones). Do you really think the linens are switched out on all of those after each departure?

Now let me put this into your head... just think about what the previous guests were doing in that bed that you had just slept in...