Put simply, Officer Delinko is sucking up to Mr. Eberhardt to try to boost his career. The implication is that normally, Delinko wouldn’t inform parents that a kid who maybe looks like their child was behaving oddly out in public; Delinko is doing this on the off chance that it’ll help him advance. Readers, however, can deduce that Delinko did indeed see Roy, and the Eberhardts’ reaction confirms that they’ve taught Roy to trust adults in general—and law enforcement in particular. But out on his own, Roy is making different choices than his parents might want him to.