Unscrupulous sellers will just send a random nothing to any address in the buyer's suburb then when the buyer asks where there item is the seller says it show in the tracking as delivered and either the buyer loses out big time and probably won't use ebay again or the buyer knows what they are doing and Paypal end up having to make a discretionary payment.

How's that any different to C&S? They could just as easily send 'nothing' in a C&S satchel.