Public protest in private spaces

With the commodification of public space (i.e. the recent debacle in Silver Spring with the Peterson Companies attempting to enforce restrictions on photography), and the long time holdings that shopping malls, while they have supplanted downtowns, don't have the same responsibilities for the public sphere and free speech, that the California Supreme Court has ruled otherwise, see "Court upholds protest at mall," from the Los Angeles Times, is welcome.

However, Chris Brewster writes on the urbanists list that Marsh v. Alabama (1946) has made the case for decades that private places that function as public places have Constitutional responsibilities, stating that:

As development patterns have ventured back out of malls and most recently become more akin to historic "company towns," it matters less and less if the property is private or not. I am sure this case will be tested soon in some factual pattern due to the evolution of development patterns.