First off, this Hyatt only has rooms with 1 king or 2 queen beds. So you at least had a king bed.

Secondly, how many people were in a room with 1 king bed? Fire marshall says only 3 people can stay in those. So you do have a legitimate complaint there. Of course, if you did not include the kids in the number of people traveling and the hotel was unaware, then they didn't know a two queens room was necessary.

Then, when you show up needing a double room and none are available, they can do nothing. In that event, you're lucky they let you stay at all. Room types are not guaranteed except for Diamonds. So if you said only 2 people are in the room, then they may have put you in the king because of that since they were running sold out.

On the other hand, if you put 4 (or however many travelers there were) in the original reservation, the hotel committed a major faux pas in assigning you a king room. And the fire marshall wouldn't like this at all.