I really hate being forced into these schemes that require that I have my iPhone at hand all the time
Another advantage of wearing pants with pockets...
From the Apple link:
If you don't see the option to turn off two-factor authentication on your Apple ID account page, that means you can't turn it off.
If someone has turned on two-factor authentication for your Apple ID without your permission, you can also turn it off from the enrollment confirmation email sent to your Apple ID or rescue email address. Click Turn Off Two-Factor Authentication at the bottom of the email to restore your Apple ID to its previous security settings and regain control of your account. The link is active for two weeks after you enroll.
That assumes you got the email
and that the "someone" used your Apple recognized email addy's.
What's the point of
ANY time period?
The "someone" usually refers to an employer IT Administrator. The 2FA may be a requirement of the employer. If that is the case, only that authorized "someone" should have the ability of turning this ON/OFF. It should also apply only to employer supplied iDevices. If you are allowed to use your own device to access employee related data, that should after signing a document to relinquish control of your device. If employer data is accessible by an unauthorized device (person or not) that should be grounds for legal action. Otherwise, don't preach "security" if the employee can disable it and still have (unauthorized) access.
Our bank allows finger-ID verification. A handy concept Apple seems to have crippled by removing the physical ID button from some newer models.
I can only hope that, when my iPhone 6 finally dies, I can then switch to facial ID or DNA sampling or brainwave comparison or ...