Blacklisted phones can be tracked when it gets connected to the mobile network whatever the sim card is belong either the owner or any one else as the tracking depends on the IMEI number not the sim card the only confusing reason is when the device gets switched OFF.
Checking the Device Blacklisted
Better to check the device blacklisted status before purchase as if its blacklisted so it will be useless, in more details when the phone passes the IMEI to the cellular network, the network starts checking its blacklisted status first then choose to register the device on the network or refuse it, but now the carrier knows the tower that gets communicated with the IMEI, so it can track it.
