Not sure I fully agree with this. While you're right that may have enabled them to sort out their problems, I don't think it's something they should have needed to know about if the bikes were correctly set up. Front mechs don't "go out of trim" if they are set up right.
I got my first non-friction-shift bike about 4 years ago. Very occasionally, due to maintenance I've re-indexed the gears. Apart from that I've NEVER touched the barrel thingies, certainly not on the fly. And, I might add, I've never dropped my chain (apart from during accidents). And I've done a fair few km.
So either my bike is a super amazing brilliant example of reliability, or their bikes were set up by chimps who didn't realise you needed to re-check the indexing after the new cables had settled in, or (here's a thought) they were deliberately set up to go wrong to give us a bit of exciting telly.
I do drop my chain occasionally on my friction shift bike, but I can pretty much always pick it up again without stopping, just by pedalling gently and using the shifter. I've never had to try that on an indexed setup, but I expect it would work (providing you aren't going uphill and grinding to a stop).