If the rate is $1.35 when you book the reservation, I think that the hotel should honor it. That's the rate you both agreed upon.

There are plenty of times I will only make a reservation at a particular hotel because I'm getting a especially good rate. If that rate is not honored, I've lost the opportunity to find a good rate at a different hotel.

However, if you book a $135 ressie and then it gets accidentally changed -- either up or down in price -- I would expect that it should be corrected since it's not the rate that was agreed upon.