You can hardly pirate something that has not been released or is impossible to buy.
Of course you can. In all my years of constant (for example) music hunting, I've seen far too many times a finished product being leaked and spread on the Internet ilegally, and it usually doesn't go away.
Trying to activate it now
is a form of piracy, it doesn't matter if it's still not available for purchase.
Also, it is true that many people did it with Windows 7, perhaps even of SF ( I wouldn't know, I don't think I was around at the time)...
You, however, like (I would assume) most others (in this community) are standing on that thin line between outright piracy for the sole reason of "stealing" ie. not paying for a product and the fact that the trial period may not be enough to suit your needs for testing, tweaking, and as you mentioned yourself, feedback.
Windows 7 was great partly because of the giant amounts of feedback given by those who wanted to test it, one way or the other (activating or not).
In the end, it matters if you actually buy the thing, not what you do before it (unless you actually spread it around ilegally). It is kind of a touchy subject that is even against the rules, I but will only dare say this: if you end up with the actual product in your hands and cough up the cash, "hacking" it beforehand is acceptable... in some cases, not all. With Windows, I both do and don't agree with you, but I understand and accept your reasoning. I guess I just still have faith in humanity xD