It's only illegal if a government law enforcement person does it. The store can do what it wishes with regard to such things.
The store can do what it wishes to a point. It can certainly request to search your items, but I'm unsure it can do much if you refuse.
As for me personally, if it's the store's bag I could care less. If it were, say, my personal handbag then there's no way I'd let them search it. Of course, I don't carry a handbag, but that's not the point!!
I just can't understand why people always believe that limits on the government should apply to private entities.
This applies typically to First Amendment rights ("Why did they censor my forum post? Haven't they heard of the Firsy Amendment?").
The nice thing is that this sword cuts both ways - they're free to ask to search my bag, and I'm free to give them the finger and keep walking.
Unless of course they have "probable cause", which can be anything they choose.
You know, like a seat belt violation, smoking where your not supposed to, wearing the wrong t-shirt, those kinds of things.
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.
We are endowed with certain unalienable rights by our Creator (as per the Declaration of Independence). The government derives its power from the governed (us), and so, necessarily has fewer rights than we, the governed. The Constitution explains those restrictions on the government. The Fourth Amendment states that the government may not conduct unreasonable searches and seizures, but says nothing of private citizens or corporate entities. In fact, the 10th amendment says that any right *not* mentioned is reserved for the states and the poeple, respectively. Therefore, odd as it sounds, the right to conduct an "unreasonable" search is restricted from the government but reserved for the people.
The store has a reasonable expectation that x percentage of their customers will steal from them. Since they have no way of knowing *which* of their customers comprise that x percent, it's reasonable that they take a simple measure such as checking your bag against your receipt to protect themselves against such loss.
Government can legitimately search bags or persons of any entering government buildings.