Those articles don't really say what the "botch" is. Was it the anesthesia? The actual endoscopic examination? Removal of polyps?

If its the polyp removal, I can certainly see how that could lead to problems. But you're a little stuck: even if you use another technique to do the scan, you still have to remove any polyps you find, don't you?

yes I've had both a colonoscopy and a sigmoidoscopy (less invasive colonoscopy).

I'm not sure what the botches are here. In the sigmoidoscopy they took out a couple of polyps, in the colonoscopy (more recently than the sigmoidoscopy) they just did a cancer check-up given family history.

I wish those articles discusses the "botches", I'd like to know since from my understanding these are pretty safe procedures

I did mine without anesthesia/sedatives. There were moments of discomfort when they pump gas to expand the area - feels like a big fart is stuck in your gut - but otherwise no big deal, especially knowing that the pain is not dangerous. Recommend. It eliminates recovery time afterwards (you can drive yourself home) and increases safety.