Not much of an issue for devops folks but a big issue in sales and marketing.
I wonder if companies allow a sales phone number be switch to a competitor when the sales person switches jobs. This is what happens when Jane changes jobs.
Customer of company A calls Jane who has just gone to company B:
Jane: "Hi Sam, I am glad you called. I now work for B and let me tell you how their product is much better for you..."
There are other jobs like customer support that have similar problems. In this case you want your customers when they call the cell phone to reach someone who works for the company.
The above problems also apply to IM handles.