I suspect in many cases it's a "Plan B" rather than a first-shot strategy. It is, of course, hard to know for sure, but as a counter-example, look how they de-fanged the FDA for regulating nutritional supplements (this goes back to the '90s). The first thing the industry did was to get every sympathetic (or buyable) politician and talking head to start talking about how Americans were hurt by the stupid FDA, using the usual hyperbole and emotion-stirring anecdotes, so that people had the FDA, out of the blue, on the tip of their tongues and "knowing" it was bad. Newt Gingrich was a point-man for this effort. (Once it was passed people started dying from ephedra-based nutritional supplements.)

Then when the legislation was produced a support-base had already been formed. They expected a very public fight and prepared for it.

In this case they were very quiet. The first thing I heard at all in the normal media was on the radio driving to work this morning. The news guy on the Boston station mentioned Wikipedia's blackout tomorrow and mentioned SOPA as the reason. The who bit was about 3 sentences. As I said, I'm not privy to insider strategy, but it was definitely a different tack.