No, and in fact this is a pretty good way of getting a big settlement check out of the district if you're willing to suffer the hassle of an (illegal) arrest.
replyWhich means it's not a good or obvious way to tell if something is illegal or not.
replyCops don't show up for civil offenses and most criminal offenses (particularly white collar offenses). Cops are also notoriously bad at understanding the law. Funnily, an illegal arrest is a good example of where the cops don't show up to arrest someone for breaking the law.
You are using faulty logic to determine what is and isn't legal.