Red Bull RB8 - rear floor cut-outs

In Monaco there was much discussion about the legality of the Red Bull's floor, with speculation that rival teams were considering lodging post-race protests (none ultimately did), despite the fact that Red Bull have been running the design since Bahrain with the blessing of the FIA scrutineers. Discussion surrounded the rectangular 'hole' in the floor situated in front of the RB8's rear wheels (red arrow in left-hand drawing). 

Article 3.12.5 of the sport's technical regulations states that, "All parts lying on the reference and step planes, in addition to the transition between the two planes, must produce uniform, solid, hard, continuous, rigid (no degree of freedom in relation to the body/chassis unit), impervious surfaces under all circumstances." Talk focussed on whether the cut-out on the Red Bull constitutes an enclosed 'hole', hence meaning the floor is not 'impervious', as opposed to the cut-outs in similar places on the Sauber (red arrow in right-hand drawing) and Ferrari, for example, which are open at the floor's edge.