My impression is that it is more common for kids. Still completely and ridiculously unnecessary IMO. Exactly how is practicing pushing buttons and administering saline without seeing the results of actual insulin being dosed useful???
What my daughter and I did was play "the nodding dog" game. We both smiled politely and respectfully as we both started saline-filled OmniPods at the "pump training" appointment after we received her pump. (I had already done many, many hours of homework with Gary Scheiner's Think Like a Pancreas and had reduced my daughter's long-acting basal dose the night before her appointment. And she was already using the Dexcom CGM.) We said thanks and goodby at the end of the appointment, walked to the car, removed the useless and wasted Pod, filled another with her rapid-acting insulin, and started "cooking with gas" from then on. At the next week's follow up appointment we pretended like it was the first time using a Pod with the real stuff. If I had had my way, my daughter would have been pumping the day after her diagnosis. Much better control of BGs with a pump compared to MDI, with much more freedom to "graze" which has always been my daughter's eating style.
And I can't sing the praises of being able to have different basal rates throughout the day and night as needed loudly enough, not to mention the beauty of temp basals!