Should brake fluid in a new car be changed after three years?

I have just taken my 2016 Ford Kuga in for its three year/30,000 mile service. Ford apparently does not change the brake fluid unless you specifically ask for it to be done and it is at extra cost? Surely...

Does brake fluid need changing every two years?

My garage informs that my brake fluid should be changed every two years. Is this necessary and will it affect my warranty if I choose not to have it done?

I've been told the brake fluid of my two-year-old car needs changed - is that necessary?

My two year old Ford Fiesta auto is due for its service and I have been told that the brake fluid also needs changing. Is this necessary?