Back in 1989, my daughters were 5 and 9, and we did a round the world trip that involved Pan Am and United, so I signed them up for Frequent Flyer accounts. The United application needed a signature, under the comment, “I have read and understand these rules.” The 5 year old happily printed her name. The 9 year old read through the form and told us that she could not sign the application because she did not understand the rules. It took much back-and-forth, and probably some increased volume of speech to get her to sign the application.

I recently picked up a mileage plus application at an airport, and similar language is still on the form. However, the website seems to merely ask people to certify that “I accept the terms and conditions.”