I think the bigger issue is if teams like Ferrari and McLaren believe there is some sort of collusion between RBR and STR (or the potential for collusion) then it might encourage them to get some leverage with other teams.
It’s been jokingly mentioned here but what if Ferrari bought into HRT? What if McLaren added to their technical partnership with Force India? What if either of them became major sponsors of Caterham or Marussia? The worry for me is that this will progress to a point where you’ll have Red Bull, Ferrari, McLaren and then the rest of the grid will be Red Bull B, Ferrari B, McLaren B, etc.
Ferrari have already been talking about running a third car and whether or not STR help RBR on track, it can’t be a coincidence that, after RBR had pretty much wrapped up the titles last year, STR suddenly made massive progress with their exhaust/diffusor. It doesn’t sound far fetched at all for this to extend to everyone having B and C teams to get an advantage, if for no other reason then to cancel out the advantage that other teams have.