"It amazes me how many people don't understand that the Constitution sets forth the limits of what the *government* can and can't do - not the limits on private citizens."
And what sets the limits on private citizens?
Do you think that just because the Constituion "says nothing of private citizens or corporate entities" that they may violate rights at their will?
"We are endowed with certain unalienable rights by our Creator" to include life and liberty, and according to the Fifth Amendment we are not to be deprived by the government "...of life, liberty, or property, without due process of law...". But just because the Fifth Amendment "says nothing of private citizens or corporate entities" doesn't mean that they are free to so deprive us.
Again, what sets the limits on private citizens? Let's go back to the Declaration of Independance:
"That to secure these rights Governments are instituted among men."
And since "The government derives its power from the governed (us)" we ourselves acting through the Government as limited by the Constitution set those limits (at least if it all works like it's supposed to, but that's a different problem).
And one of the limits I (as one of the governed from whom the Government derives its power) want set on private citizens (including myself) is to protect The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures
If you don't go into the store you don't need to worry about searches, reasonable or unreasonable.