Residency is not the same thing as tax residency. In many places, you can get residency without becoming tax resident. Banks often just want to see an address and utility bill, not proof that you are tax resident in that place.
This is correct, therefor banks have the option to select there is no TIN available and one can add/select the reason why no TIN is available.
Definitely banks have a list of jurisdictions that don't provide a TIN, so I believe one can assume that not providing a TIN will be accepted for some countries you are resident and for others not.
