Pairing Bluetooth speakers I'm looking at buying some Bluetooth speakers, I haven't used Bluetooth in a long time and can't remember exactly how it worked.

If I pair my phone with the speakers, what's stopping someone else attempting to pair with the speakers?

Once paired do the devices become undiscoverable?
You can pair Bluetooth speakers with multiple devices.  My Bluetooth speakers are paired with BOTH  my tablets, my phone and my laptop.  You cannot not, depending on the device, connect via Bluetooth to more than one device at a time.

Pairing doesn't make the Bluetooth device undiscovered.