More likely, I wonder if their model considers the natural decay of other chlorofluorocarbons, like R-115, R-114, or, counterintuitively, R-12. It's probably reasonable to expect that as those compounds break down, that R-11 could be an intermediate step.
Crushing up old closed-cell foam, old cars, old refrigerators, and old industrial plants are all possibilities if the above is not what's actually happening.
It's remarkable how we as a society have declared victory on our ozone problem, when in reality, it's not been fixed. Did you know that the UV index outside can actually go way above 12, like 45? Nobody measures this, but it happens.
Spending all day at the beach with no sunscreen hasn't always been insane, just since we started our experiment with refrigerants.
In the industrial context, there's a whole bunch of worrying things that had to be learned not to do the hard way but were probably obvious and emergent discoveries making them likely to recur without sufficient intervention/education.
At least our mistakes were made with relatively small population multipliers. Repeating them on the scale of China or India's population, there's massive potential for environmental harm the likes of which we've never seen.
Could be nonsense, though, if there are better coolants available today that are legal.
This is not my field of expertise, and a quick googling didn't turn up really unbiased sources.