That's only for track testing, which the article doesn't really make clear. They wouldn't send a fleet of mechanics to accompany a group test if the car was only being road-tested. But testing a road car, even a "super" one, in an environment for which it's not intended, where a car would usually be accompanied by a team full of engineers? Yes, they send some then. As do Lamborghini, Mercedes, just about any car maker of size you care to mention. They want the data too, it's extra testing for them somewhere where they may not have tested the cars themselves.
Fettling the car before a test? Been going on for decades. Any Jaguar E-Type owner trying to match the posted top speed of the pre-production cars used to set said speed would have struggled, as would the XJ220 owners of a couple of decades later. A 60s muscle car owner attempting to match rated power on a dynometer would usually be disappointed.
Not saying any of it is right, or that I'm on board with Ferrari putting its name on everything or trying to skew tests in its favour, but equally, singling them out like that didn't seem quite right either.