DynamoRevit wraps the raw Revit.Db.Elements with wrappers. These wrappers when constructed via constructor nodes, document queries, or selection nodes, return wrapped elements. The wrappers implement element binding by linking the element ID - > a callsite -> a node in the graph.
I think if an element is RevitOwned it usually came from a selection - or you called the method with true - and these elements will not be deleted by Dynamo.