then we can expect a cascade of similar legislation banning taping in non-profits (Acorn), pseudo-private areas, etc.?
What raynier is saying (I think) is that if it is illegal to trespass, then it is illegal to trespass for purposes of whistleblowing because that is still trespassing - imagine if they had trespassed, filmed, and found nothing illegal. If one of the farm workers were to film the video, there would have been no trespassing - it would constitute whistleblowing.
Not exactly. What I'm saying is:
1) The Constitution only prohibits governments from restricting free speech;
2) What you do on other peoples' private property is rarely if ever considered free speech or free expression.