If WDW wants to take my fingerprints in order to let me in, they can have them! I have nothing to hide. My fingerprints aren't top secret - heck, I leave them on every glass I use at restaurants, on doorknobs - on everything I touch. Mine are even on record from when I got my handgun permit down at the Sheriff's office.
If these new routines are being put in place to A) Keep the parks safer, and/or 2) to help keep ticket prices lower than they WOULD be, by minimizing overuses - then I'm ALL for these security measures.
Someone mentioned face scanning cameras. I would encourage them to install them. Many professional sporting arenas have them in place already - although most people don't realize it.
You're on Disney's property - you're using their facilities - they can use whatever means and methods to ensure legitimate entry and authentic identity that they want, and the ACLU *shudder...cringe* can try as they might, but can't do anything about it (thank God).