Hoo boy. Absolutely not true. The only areas in science that are invalidated by my argument, are those areas wherein ID has to be invalid. To my knowledge, the only area of science claiming this is evolutionism. Everywhere else, the art is advanced by designing experiments to test hypotheses - their very nature not only assumes, but demands ID. If not so, then the results would be useless.I don't understand your point. You claimed that any experiment that was intelligently designed could not rule out ID, therefore only experiments that were not designed could rule out ID. You claim that the very fact that an experiment exhibits design makes it unable to detect the cause (or rule out a certain cause) for a natural phenomenon. It's like saying "this experiment cannot apply to phenomena that exist in Japan, because none of the test equipment was made in Japan." It's a non-sequitur.
It just so happens there's a similar controversy in meteorology: Godless materialistic meteorologists claim that there's ice in the winter because the temperature drops to below freezing. But a loud, very small but well-funded minority claims in the popular press that there is an Intelligent Ice Fairy who only comes out in the winter who produces ice.
So let's try this experiment:
A. There is ice in the winter because the temperature drops below 32oF.
B. The experiment & apparatus were intelligently designed, therefore it cannot rule out the Intelligent Ice Fairy who only comes out in the winter.
Well! Now it becomes clear just what the IIF'ers are really saying: No amount of materialistic explanations will prove IIF theory wrong because there's always the possibility of a really sneaky Intelligent Ice Fairy out there (cousin, no doubt, to the cobbler's elves) who diabolically changes the environment in exactly the way needed to perfectly cover His tracks.
Don't you see? This would be the only reason why an experiment would never rule out IIF (or ID). And the fact that the experiment itself was "intelligently designed" is irrelevant! I'll bet you can't even describe to me a "non-designed" version of the above experiment.