Families with 3 children - Can Disneyland change the rules?

Simple maths:

If the maximum family size is two children, then this is insufficient to replace the population at each generation, due to some people having only one child, choosing to have no children, being unable to have children or dying before reaching adulthood.

The fertility rate in the UK is approx 1.73 children born/woman

Not including effects from immigration, this means that in one generation (30 years) we will have 1.73 people for every 2 people alive today. This means less people to pay for services which the adults of today will need funded in their retirement (e.g. police, hospitals etc).

Clearly then population replacement would seem to be a Good Thing.

However, the places you think would be most welcoming of children still stick to the "2 children only" rule.

Today, I received yet another competition with my daily paper (this was a trip to Disneyland). Once again it was open to a family. Once again a family was defined as being a maximum of 2 adults and 2 children and once again I didn't enter because it would have meant leaving a child at home.

I wonder how many prospective customers the people running these competitions lose through having such inflexible rules? How about simply apportioning a prize fund to be spent at the resort, including travelling there and spending money and then leaving it up to the winner how many people to take along?

To see how commonplace the "2 children maximum" rule is, see the following resultset for competitions to Disneyland

No prizes here for three children