Al least it proves that the A380 doesn't have too much wake or induced turbulence (even if they carefully avoided flying immediately behind the aircraft itself, in a way very similar to fighters positioning prior to in-flight refuelling)
Undoubtedly those two gentlemen (french-swiss and french) had ironballs: the slightest mistake in flying too close to one of the invisible vortices and that would have been an uncontrollable sudden departure (remember the XB-70 Valkyrie mid-air collision on June 8, 1966, when an aircraft much bigger than those flying men was sucked within the wake of the massive bomber..)
As for the pilot flying the 380 ... well ... apart from performing holding patterns with flaps down, I don't really see the point - but they will probably explain in the next couple of weeks that they did rehearse for hours on simulator !