Exactly. If he had Borg tech still in him, then it's possible at some point the Borg could trigger something to happen in Picard whereby the nanoprobes would awaken, or somehow gestate and start converting Picard's mind to be with the Collective, maintaining a human appearance while being a drone purely by mind alone.I'll never understand how Picard was allowed to resume his command, if Starfleet knew that there was still Borg tech inside him.
Yep, they'd never have let him continue in Starfleet let alone command a starship.