Theses gems stuck out for me:
Eighty percent of all input forms ask questions they have no business asking.
A procedure should fit on a page.
And especially: Don’t make the user provide information that the system already knows.
This happens all the time, especially in e-commerce. And even moreso in paper form. For example, every time I go to a new doctor, I have to fill out 15 forms and 15 times I have to write down my name, address, SSN, insurance id, etc... Why can't the doctor's office, which already knows all of that, just print out 15 forms with all of that pre-populated?
Somewhat related: We build so many input forms demanding people provide data to the computer in a form that the computer can immediately read. The computer should work for the user, not the other way around.
Example: The FCC's Do Not Call web site has notes on its input fields that phone numbers have to be entered as numbers only. No dashes, parentheses, etc... How about the web site take whatever is input and strip out anything that's not a number? So basic, but I see this all the time.
Which brings us the principle:
Never ask a question whose answer you already know
If you know the answer already, why does the question exist on a form?
For the CS/programming side of it -- do you really know what you think you know? A smart form should let you put in house address and ZIP and look up the rest, but frequently developers think they know more than they actually do, and it's not a bad idea to have the user confirm or possibly override the information. Depends on the situation, really.
No you do not.
Anecdotal: I always leave that field blank and have never been asked for it.
Anyone can ask you for anything, anywhere. It doesn't mean they actually need it, or that you have to give it to them.
I went to a dealer to buy a car in cash (well, a cashier's check). They had a touch-screen computer with all their forms for me to fill out. It came to a credit approval/application form, and I refused to fill it out because I wasn't opening a loan. The lady assured me it was "standard" and that it wouldn't be used for anything, because I didn't need the loan/credit. I kept refusing, and she kept insisting they only needed it because the software required it to continue. After this impasse, I stood to walk out, and she suddenly changed her tune and somehow "figured out" how to bypass the form. Classy.
That's why they had a cashier's check and not a personal check.
Because, considering it sounds like you bought the car outright, there's absolutely no reason for that form to need signing.
> You are not required to have a social security number to open a checking or savings account.
Having spent more than a few years in FinTech, I know these things can vary from company to company as companies generally are required to design their own “risk-based” policies for AML and KYC.
(I'm not undocumented, but I imagine they see that enough which is why they don't bother saying anything when I leave it blank.)
I'm pretty sure they just want your SSN for collections/credit-reporting purposes.
Yet still, today, its a very rarely encountered technique. I wonder if so much has changed in the Zip+4 world to make it an efficiency sink...
Backwards paper systems serving the moneyed interests.