This is where the laws need to be tightened -- people tend to not know what their rights or obligations are, and have to rely on expensive professionals to advise them (and it can still go wrong). When a government agent makes a request, often it can come across as a demand, with the implication that your are required by law to comply (they can even lie to you to get you to comply).

Now in the case of a large business, I would expect that they have the resources to figure out when to comply or when to ask for a warrant. But individuals have a harder time -- imagine getting sued by your employer for complying with a TSA agent's demand that you open your laptop for them to search through, then you get sued or fired because of that. It should always be illegal for a government official to imply that you are required to do something, if that isn't the case (and make it clear that there is no penalty, such as not being to board your plane, for not complying).