I agree with the OP, the WOH language is often unclear. As to 48 hours prior to check in, I would much prefer just a stated time and date. I don't keep track of when check in times are and I don't know why I should since that time has no significance anyways. (I generally check in whenever I show up, whether it is 8AM or midnight and it seems just as common to have to wait for my room to be done after 3 as before 3 because successfully checking in has to do with occupancy, room type reserved (or upgraded into), and housekeeping employees vs # of rooms turning over).