[toufka]

As a practicing (biomedical) scientist I can say that the claims get bolder the higher the publishing cost. This is because the highest costs generally are associated with the most prestigious journals, and you won't be published in those journals if your paper doesn't make bold claims. The same exact set of experiments can be sold a number of ways - and when you shoot for the prestigious ones you try to sell it as hard as you can.

The correlation isn't perfect because some of the newer, more prestigious, open source journals are pretty well curated.