I'm no expert, but I doubt there are too many radiologists around who are going to misdiagnose a condition by mistaking an artifact caused by a faulty probe (which are usually pretty obvious in my experience) for something more serious.

Also, the last time I was at [3rd-Party Service Provider] I was quite impressed by their nifty probe testing equipment. I doubt that any OEM has anything much better.

Lastly, during some of my experiences in the ... umm ... Third World (many years ago, admittedly) I came across a fair number of cases where sonographers were able to carry on doing useful work simply by being aware of the "straight black lines", or "black dots" (etc.), created by what were obviously partially defective probes. They would make allowances for the defects, change the position of the probe, and try again a few times "just to be sure".

I'm not saying it's right; but just reminding of what can sometimes be the reality of the situation in some parts of the world.

On your last point Mike ... can you provide a citation (Chapter and Verse) where any of that has actually happened? think