I lost my phone a few weeks back and was astonished that I was able to go into T Mobile and get my number switched to my new phone without showing any ID
It was just a web form with a few boxes to fill out based on customer provided info followed by enter.
Even when ID is checked, a decent fake ID is like $50 these days, and grants access to wealthy bank accounts.
At the time we were heavily incentivized to speed run anything that did not generate a commission so checking ID carefully if at all was not high on our list of priorities.
One would hope it’s not possible to swap unless that is entered, no matter how corrupt the employee.