One example of how this can be used is with an upstream protective device trace. The first call to the Tracer will return the first upstream device that meets the protective device criteria. To find the next device upstream, you would set a starting point on the device returned by the first trace. With IgnoreBarriersAtStartingPoints set to False, this second trace would immediately stop at the starting point, since it meets the trace termination criteria. Setting this option to True will allow the trace to ignore the starting point, and continue to the subsequent device upstream.

Reference

TraceConfiguration Class
TraceConfiguration Members