RR, what's funny about that statement is that almost all forensics analysts tend to fall back to "I know what I'm doing and I am saying that I did it correctly." The defense lawyers will always attempt to attack your abilities and knowledge first because it is the most common area of weakness. If you can't demonstrate that you know what you're doing then you'll probably get exposed. If you can demonstrate it on the stand, then they'll attack your tools. This is harder to do because most of them have been vetted already, but there is always a chance that they can convince the court that something went wrong. Hardware write blockers have a known failure rate, there can always be something in the tool/platform settings that could screw up the evidence, a cosmic gamma burst could have randomly scrambled those bits on the hard drive so that they magically turned into a picture of a little boy in a sprinkler, etc. This is more of an exercise in confusing/scaring the jury. If they can't get you on your knowledge or your tools, then they'll try to attack your integrity. At the end of the day, everyone who testifies is basically saying "I did what I said I did."
CISSP, CISM, CISA, GCIH, GREM, CEH, HMFIC, KTHXBIROFLCOPTER