I'm pretty sure they're not dummy fields.A more logical note is that the dumb programmer they had working that day thought this might be a good way to discourage people from trying to guess the correct input fields so he put up a ton of dummy ones to try and confuse you.
AJAX when done correctly actually makes your source code cleaner and easier to work with not messier.
And I didn't say there was anything inherently wrong with ajax. Just with the ways in which it is frequently applied.