In this case, not standing up for your rights might not only be more convenient but also the right thing to do. There are no constitutional protections that prohibit congress from giving merchants the right to search their customers while on their premises.
If retailers feel that shoplifting or lawsuits brought by guys like the author of this article become too much of a problem, they are not above lobbying congress for such laws to be passed.
Allow me to translate that post:
“BE AFRAID!”