Why does Raccoon need a Google Service Framework (GSF) ID?

Raccoon doesn't, Google Play does. Among other things, your device ID serves as a hashkey for your device's configuration which is needed to search for compatible apps. If you don't provide the device ID of an already registered device, Raccoon will simply create one itself and hook it up with the configuration of a Samsung phone.

NOTE: Google does not provide means for deregistering a device. If you force Raccoon to generate an ID of it's own, you will be stuck with the according phone in your account.