Scan responses from the peripheral standpoint are for active scanning, to give more information to a central device when it queries the device for information.
Passive scanning doesn't require this iirc.
But, the central events for scan responses are necessary for the connection process, as they are the only way to handle peripheral advertisement packets being detected.
I believe the BLE can be set to advertisement nonconnectable on the peripheral, and that should eliminate scan responses, but I'm not completely sure about that.
