I've discussed whether, and to which extent, Bluetooth Marketing is legal, in a couple of articles, last November:

• Can a Police Bluetooth Network Be Illegal?
• Protect Your Proximity Marketing Campaign From Being Called SPAM

Since then, not much has changed legally, and no news laws have been voted here in Greece, but it is stil important for everyone involved in the industry to have at least some guidelines established, so there is some common ground between marketers, in order to protect the image of bluetooth marketing as a whole -- and avoid it becoming widely recognised as bluetooth spam.

This is why it's big news every time the DMA or the MMA announce a new set of mobile marketing guidelines.

This time, the DMA has beat the MMA into announcing its newest 'Mobile Marketing Best Practice Guidelines' (the MMA has an announcement for new guidelines in May).

A few relevant extracts from the DMA guidelines:

It is therefore advised that the same standards should apply as any other form of mobile marketing such as SMS marketing. This means that marketers need consent from the intended recipient before sending a Bluetooth marketing message to their handset. See previous FAQs on consent. To be clear though, consent can be easily obtained via the ‘call to action’ routes outlined in the examples in 3.9.1.
We believe that this approach – though admittedly considerably more rigorous than is legally necessary – is right because of the principles of permission marketing. In addition however, it should be remembered that Bluetooth – unlike other mobile technologies – can deliver applications that will add to, or even alter, the handset's functionality. Given the potential significance of installing applications via Bluetooth, we believe that it makes the requirement of clearly seeking the user's permission all the more important.

...

Bluetooth technology actively listens for devices as they come into range and formulates a message specific to that unique device. Similarly, once a user activates their Bluetooth device, it becomes visible and actively pages other devices thereby advising the fact that it is in this mode.
Whilst technically it might be argued that the very act of activating Bluetooth is therefore both consent and a response to a call to action, it is our view that neither is so. In the examples shown in 3.9.1.1 and 3.9.1.2, consent has clearly been collected and the medium is being used effectively and without any contention over consent.

The DMA 'Mobile Marketing Best Practice Guidelines' are certainly useful and recommended reading for anyone in the field, more so, if you are just looking to start..

Regarding how legal Bluetooth Marketing still is, well the answer is, same as before.. We've now just got more guidelines as to how to provide better mobile marketing services.