If Pirelli wanted to influence the outcome of a race, they would produce a run of identical tires for the race they wanted to influence. However, the construction for the tires in that production run would be based upon, and optimized for, the specific team/driver Pirelli chose to favor for that race. Such is made possible because of the reams of data Pirelli has for every team/driver. Those identical tires would then be allocated to the teams by the FIA*. On the surface, none of this would appear to be abnormal.
The favoritism comes into play when teams A, B, C, D, E, F, G, H, I, J, K, and L are each allocated identical tires from the FIA that are nonetheless optimized for team C. In this manner, the favored team could be different for every race, and because teams are having considerable difficulty figuring out the tires, it's likely that no one would notice those changes. If someone did indeed start asking questions, Pirelli could easily claim natural variance from one production run to another.
Like I've said repeatedly, it's extremely unlikely this is actually happening. That doesn't change the possibility that it could happen, though. (It probably won't. I cannot stress that enough.)
I only mention these things because this is probably the most F1-related fun I'll have while F1 is in Valencia.
* FYI: Tires are produced throughout the season and then allocated by the FIA on a race-by-race basis, i.e. Pirelli doesn't just make a massive batch of tires at the beginning of the season and then hand them over to the FIA.
EDIT: I gave it some attention-grabbers. I want to leave little chance that important points can be easily glossed over.
to be honest, nothing would surprise me.
F1 is first and foremost, a business. This 'exciting season' (to me its not at all but it is for your casual louty football yob viewer) coincides perfectly with that flotation. What better way to boost the share price than trying to show the sport in the best possible commercial way. After all, 6 different winners, who could argue with it not being exciting? From a business perspective its got potential for growth.
switching tyres is highly improbable really, given the complexity of actually doing that (although youve made it sound simple, in practice i'd imagine theres all kinds of logistical issues, and imagine trying to keep that quiet?).
but if it is true, its not difficult to understand why they'd do it, theres a clear motive.
when a bank makes a loan, it creates the money out of nothing. that seems mental in itself, yet it happens every day.
anyway, heres what f1 used to be like....