If you try to book ski holidays online with Tui Group (Crystal, Thomson and First Choice), the price for one adult and one child is more than the price for two adults!
I tried to book one of their holidays through an agent by phone, who told me that the total price was higher because the price online was only updated once a day [shocked]. So I called Crystal to check and ask why it was cheaper. They said the child price is the same as adult price but it's just that there is £50 off per adult (although the agent did say per person at one stage and so does some of the online literature!). Only after asking to complain to the supervisor and spending forever on hold was I able to get the same price as two adults for me and my child!
Be wary of this if booking anything other than two adults and children.