why do some lower prizes ask for your age surely if you are mrs you must be old enough to enter is it because the prizes only go to people of a certain age

Worryingly I have found instances where the age brackets don't go as far as my age!

A lot of entry forms seem to be a standard format. I believe the companies offering the prizes use promotion companies who will use standardised forms rather than going to the trouble and cost of customising the layout for each client.