I think that sometimes the property makes the rate available where it wouldn't normally be according to the rules, because it is to the property's advantage (i.e., low occupancy). It seems to me that if the reservation is accepted it will be honored. However, in such circumstances I have always called the property in advance to double check. In every instance I was told the rate would be honored (and I, of course, kept a record of the name of the person I spoke to).