It's one thing for someone to try to pull a fast one over me...I just call them out on it, avoid falling into their trap and move on. But when someone tries to dupe my wedding guests -- my friends and family -- it curdles my blood! It infuriates me like nothing else!
Such was case with our hotel room blocks. Basically, when you reserve a block of rooms, you sign a contract with the hotel detailing the number of rooms, room details (single or double), the group rate and the deadline until the rate is valid. But make sure your guests know the details of your hotel block. Apparently, at one hotel, several of my OOT guests who wanted to book double rooms for their families were told there weren't anymore (not true since we should have had plently of double rooms available according to our contract). The situation required a strongly worded letter to management to get everything resolved.
Another friend tried to book her room over the phone in another reserved hotel block when the agent told her that all the rooms in the block had been booked and the group rate was not available anymore. Sure enough, I checked and there were plently of rooms left in our block with time left before the rate expired.
So when you book a hotel block for your guests, I suggest to you double check with them to make sure they received the rate you agreed upon with your hotel. If you signed a contract with the hotel, your guests are entitled to the discount. Perhaps hotels assume your guests won't know and they'll do anything to make an extra buck. But for people coming the distance for your wedding, you definitely want to look out for them!