It was designed not just to keep people out, but also to control the flow of people and goods and to administer taxes on trade. Similarly, a firewall dictates the terms of necessary interaction with the outside world and is the main tool of an accept strategy.
One of the most important questions to ask when evaluating cyber security is about the number of false positives, rather than just focusing on the number of incidents. A false positive is a sign that cyber defenses are actually in place although, of course, too many can be a major irritation and lead to dangerous complacency.
A company that has no documented false positives is a company that has no documentation procedures, or no defenses, or is lucky to an astronomically implausible degree. False positives and minor incidents are essential features behind an accept strategy.