Hello, Mochacon, so to answer this question, we must understand what and ids is. A intrusion detection system (IDS) is a device or software application that monitors network or system activities for malicious activities or policy violations and produces electronic reports to a management station. IDS come in a variety of "flavors" and approach the goal of detecting suspicious traffic in different ways. So according to this definition, this statement is true since and ids does detect intrusions, detects suspicious events indeed, and sends alerts when intrusions happen.
Hope this helped!