How to prevent unauthorized access to bluetooth speakers?

I have the Soundsticks Wireless speakers. They support bluetooth but also have a regular 3.5mm audio jack. My issue is that neighbors can pair with the speakers and play audio and I don't know how to prevent this short of turning off the speakers. Is there any way to prevent unauthorized access? Is there a model of speakers that have a security code or some other feature to limit access?

Seems the Harman Kardon Soundsticks Wireless Speaker System automatically enters pairing mode and becomes discoverable by other devices when turned on, and has no discrete Bluetooth button. As such I don't see any way to limit access to them while they are turned on, and for a product being sold at at such a premium price this seems to be an extremely surprising omission. (Strangely, no widespread complaints about this either as far as I can see.)

As for alternatives, we don't do product recommendations here so just look for a set of speakers that has a physical Bluetooth pairing button. There are lots available.