If Bluetooth marketing were mindlessly delivering content to Bluetooth handsets and their owners, it would be spam. But Bluetooth can't be used to create spam. Clients can only get a message if they want to. Bluetooth marketing is generally not very effective for simple push campaigns because the vast majority of the users have their Bluetooth turned off.
The service is an opt-in service. The potential recipient, has to:
Bluetooth is nothing like spam. In fact, successful Bluetooth marketing actually reaches people who are interested in the content being sent.