Their a little difference between a pilot telling you he is going to fly the plane and a guy peddling his invention on you! Science is not based on taking peoples word, they do in fact have to show their data and we have to replicate it and verify it. Technology doubly so, since their livelihoods live on functional products. You would be surprised how much I've learned from reading reports and analyzing their data. In fact we don't take their word, I (unfortunately) have had to replicate many experiments simply because we could not just take their word that said procedure produced specific results.