They didn't go so far as to cause alarms on unknown device ids, but devices would just not be mounted if they were not whitelisted.
This was during the windows XP era when it seemed there were an endless number of security problems related to usb devices, no matter how good the group policy and registry settings pushed via active directory membership were.
The safeguard doesn't need to be perfect, it just has to be good enough.
While these second order effects are immeasurable, they are quite tangible in my personal experience.
Attempting to authenticate USB devices is a very hard problem — a sufficiently advanced attacker can spoof manufacturer and device IDs, even if you lock things down to prevent anything other than a keyboard or mouse it's possible to send keystrokes to open the wrong website, there's always a chance of an exploitable flaw in your USB stack, etc. — but anyone diligent can be paid to walk around every week checking to make sure that a seal is solid and the tamper-evident stickers have the same serial number as listed on the inventory. There is a real value in having things where the failure modes are obvious and intuitive.
Here's a current story:
Someone ordered the wrong desk phones at your large company?
1.) Assemble your crew. Go to various departments and recruit non-technical people.
2.) Task them with disassembling 1000 desk phones.
3.) Hot glue USB port on phone shut.
4.) Reassemble 1000 desk phones.
(Due to various disability acts they can't really do it either, as the employer must provide their staff with hardware they require, e.g. ergonomic keyboards and mice)
(For your parenthetical I should clarify - it wasn't the case that it was impossible to whitelist other devices, it just had to be done on a case-by-case basis. I.e. you would call IT and say "Jen from accounting at machine foo123 needs her new ergonomic mouse to be recognized" and they would remote in, tell Jen to unplug and replug the device and whitelist that exact USB device id on that exact machine.)