Sometimes results won't replicate because the people or equipment at the second lab aren't skilled enough to do the experiment correctly. You can get type II errors on difficult tests because of impurities, noise, etc. But most of the tests listed on Science Exchange seem like standard tests, where the labs doing it are probably better at it than you are, so this wouldn't be too much of an issue.

I think another effect of this experiment-for-fee model would be to level the playing field for smaller labs that can't master every tool simultaneously. Whereas before a researcher would have to choose between (a) learning a new technique and buying new equipment and (b) finding an alternative way to demonstrate a result, presumably with older or less reliable methods, now they can do a very simple one-off collaboration of sorts without any of the overhead of real collaborations (esp. negotiations over authorship).