I saw Thomas’ post (thanks @Thomas) and it made me think that this might be a great way to subvert the Medtronic-United Healthcare lock:
https://www.medtronicdiabetes.com/products/minimed-670g-insulin-pump-system
"This device should also not be used in patients who require less than a total daily insulin dose of 8 units per day because the device requires a minimum of 8 units per day to operate safely."
For people willing to work a few months towards it with low-carb / keto diet, and who have an Endo willing to help with an aggressive fight who might be able to get down to 8 units per day, this would then make the Medtronic pump unsafe based on Medtronic’s own statement!
If someone can’t use Medtronic’s most recent pump because the company has declared it would be unsafe for them, no reasonable insurance review would require someone to use an older pump. That would never stand up to independent review.
Even if someone can’t quite get down to 8 units per day, a few injections “off-the-record” would never be known by United Healthcare. Syringes tell no secrets! 
Ha!
Anyway, just wanted to mention this. Let’s file it away as another tool for people who think they should decide on the pump they should use rather than the insurance company…