Do insulin pump bubbles cause medical emergencies?

We recently got an e-mail from another person who's had problems with insulin pump bubbles.

If bubbles in the pump cause a few strange high blood glucose readings (say in the 200s or low 300s), that's probably not a big deal - almost every insulin-dependent diabetic has these from time to time when they mis-guess the number of carbs in a meal. But a number of 420 and a trip to the emergency room is a big deal, both health-wise and bottom-line-wise for patients and insurance companies, and - we can hope - for federal regulators who are supposed to watch out for problems with medical devices.

Here is what the person said (personal identifying information has been removed):
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Hello,
I just found your information about air bubbles in the Medtronic Insulin pump.
It was as you had read my mind!!
I was put on the pump in December ....
My problems were first found Jan.... I noticed a long air bubble in my tubing as I was about to bolus for a meal.
No telling how many more had gone through without my knowledge!
I even had to go to the E.R. one night with a 420 reading!
While there...I found a 2" air gap in my tubing line!
Since that time...it's been a pain, checking...purging....wasting insulin.
I called and talked to the help line also... actually talked to Christine...and yes she's a jewel!! Very nice helpful person.
Switched infusions, reservoirs with Medtronics...changed insulins...finally got a new pump. Still have bubbles...none as large as before...but yes, I do still have to check constantly to see if there is a air gap in the line. I actually have had 5" bubbles!!
Talk about a big problem if I hadn't checked!!
I'm sending your blog and your posting in the forum to the Diabetes Clinic that I go to...Just to let them know it's NOT just me!
One thing that was offered to me was to fill the reservoir ahead of time...let it sit (hoping the fizzie bubbles will all come to the top) before changing my sets. I'm like you...I think that bubbles come in from the o-ring. When I tap the bottle to remove bubbles...there seem to be more coming from the o-ring, and that doesn't make sense.
I hope to hear back from you, hopefully with information on this problem!!