I agree that nothing is certain yet and people who're thinking of accepting (or rejecting) the offer should clarify what it is.
However, the use of "your reservation" seems - to me at least - to indicate that it may refer to the room/suite booked. To take an example of the following circumstances:
(i) a hotel advertises a mistake rate of £50/night;
(ii) I book 5 nights in the royal suite; and
(iii) I receive written confirmation of "your reservation",
I think the hotel would find it hard to later turn round to say that "your reservation" actually referred to 5 nights in the broom cupboard but not the royal suite!