@unintentionathreadkiller
We checked into a travelogue yesterday for the four of us with a cousin in tow just to see the room, check in gave us five key cards and didn't even ask so I don't think they even notice!
My brother is a manager in a travelodge and I can tell you for a fact that they would NOT give out 5 keycards for one room. The policy is 3 adults (MAXIMUM) and one child, to one room. So, either, the employee was severely breaking the companies terms and conditions, and will probably be found out when the manager comes in, and sees on the computer that 5 keycards have been issued for one room, OR you are making this up..
It's one of the 2. Because they flat out don't let more than 3 adults and one child into a room.
@janicebattersby
I’ve worked in many hotels and am wife of a firefighter, so before loads of people pile on talking about it being ‘illegal’ and some vague reference to ‘fire regs’: it’s not illegal and fire regs do not stipulate how many people can be in one bedroom at any time, so don’t worry about that.
I think your 'firefighter spouse' may need some retraining. Of COURSE they need to know how many people are meant to be in each room. FFS!
They will fully search every room where they believe someone may be trapped.
And how can they do extra searches if they believe someone to be trapped, when some people are not down as being in the hotel? Seriously, you are not even making sense!
@Weezol
If the systems are showing that rooms x y z are swiped as 'in' and four people are booked into room x, the firefighters will go to room x, look for and if necessary, pull out 4 people. If you're all unconscious, who tells them that there should also be a toddler in the party to look for?
Exactly! Some common sense at last!
@middleclassproblem
What if a single person hooks up and takes someone back?
AGAIN, if they are not down as being on the booking, a decent hotel will throw them out ! (The person who booked it AND the person they sneaked in!) for breaking the hotel rules.
@sweetmoon
I've just booked a family room and left it at that.
And you can't just 'book a family room and leave it at that,' because the booking form asks how many ADULTS and how many CHILDREN there are. So you MUST be putting SOME number in there.
Are people just making shit up for the sake of it on this thread?! 
Re the OP, yeah I am sure some people take the odd human in who is not on the booking, (and get away with it!) but let's not pretend doing this is not a risk to life if there's a fire.
And for the record, my brother (and his colleagues) have chucked people out MANY times when they have discovered 4 or 5 adults in a room (when there was only 3 on the booking,) as the people are breaking the hotel rules. So I am frankly quite amazed to see so many people claiming they 'do this all the time, and always get away with it...'