[deleted] For Bluetooth devices, "pair" means going through a protocol in which two devices negotiate a security key, typical triggered by holding down one device's power button for a long time, and often agreeing to a confirmation on the other device. Pairing is intended to be semi-permanent. It is rare to un-pair devices.
Once two devices are paired, it is expected that they are, from time to time, "connected" and later "disconnected". While two devices are connected they can exchange information; when one device is off, or the two devices are far away, they are disconnected. Two disconnected devices remember each other while disconnected -- for example, one device may remember the other device's name.
Devices may be paired for years at a time, during which they are typically connected for minutes at a time, then disconnected, many times.
Might it be the case that the question at hand would be more accurately phrased in terms of connecting and disconnecting? Also, is it possible to say more about what sort of security threat (or privacy threat) might be a concern?