It seems perfectly reasonable to me that Jolla would want to give journalists completely factory fresh phones or perhaps with a representative set of applications and data pre-installed rather than those that have been used already and had who knows what installed on them. Stefano's concern is valid.

They obviously want reviewers to have the best possible experience in a manner in which Jolla know what is on their product. From a reviewer's perspective, it's also impossible to give a fair review of a product if part of the specification is not as it came out of the factory. You have to disregard the differences and you possibly can't totally discount that those changes might have a positive or negative effect on the product. For a new, previously unseen product like Jolla that would be incredibly hard to do.