Hmm.. I can't see it as sandbagging myself.
You might make a statement about having issues when you're not to try and persuade the other teams to lay off trying to improve their cars but...
a)I don't believe any team would go as far as getting their no.1 driver to stack it to prove the point. Simple fact, Hamilton crashed more than once which proves he went past the capabilities of the car, (at least on those two occasions). So we have to conclude he must have been pushing, (relative to what the car can do), no matter how it may look to the outside observer.
b) I don't believe any team has sophisticated enough simulation software to not have to actually bother trying to find out how the car performs in the real world. At the very least I don't believe engineers and the team would put their faith 100% in such technology at the posibility of it costing them the championship. So why deliberately waste testing time by cruising and not trying to find the true envelope? I don't believe any team would ever do that. So we have to conclude they're not and they're just not able to push the car.
c) Why would Hamilton be showing signs of frustration, (taking loads of curb etc), at having slow times if he knew in reality that they were sandbagging. Or is that a double bluff? Well given a) & b) and taking in to consideration Hamiltons own temperament, (which I don't believe he has any capability to change), I don't think he's doing it to bluff, he is genuinely frustrated.