"That's the test: Have you induced someone to breach their duty of confidentiality?" he says, adding that if yes, then you've broken the law. "If I call you up and say, 'I'm working for the CEO, and he wants you to fax me Document X, which contains a trade secret,' and you do so, then my misrepresentation caused you to breach your duty of confidentiality."
It's both common and permissible, he says, for rival retailers to keep tabs on one another, to stroll around the public areas of one another's stores and make competitive use of whatever information they have gained. Nor are they under any obligation to declare themselves to be the competition, unless asked. "Companies generally have a policy that requires their employees to identify themselves truthfully," he says.
"A legal line is drawn where a misrepresentation induces a breach of confidentiality on the part of the information holder," he said.