User blog comment:The Milkman/The Writing of the Ending/@comment-5144441-20120601071637/@comment-121.214.23.14-20120604163749

The Collector shop could spot the Normandy so I suspect the Reapers can. Still it is mentioned many times that in ME3 the Normady is undetectable. Maybe Cerberus upgraded the system? Or the Reapers struggle to spot it in a battlefield? - Ironreaper