Techies tend to associate access control with legal control. Nothing could be farther from the truth, especially when it comes to legal discovery and subpoenas.

And it gets worse. The 4th amendment protects against unreasonable searches from the government without a warrant, not all searches. If you have evidence on your personal devices that a judge believes could be relevant to the outcome of a criminal or civil trial, be prepared to give it up or face a potential evidence tampering / obstruction charge. Doesn't matter if you never signed into your personal Gmail on your work computer or not. In a trial where work records are important, your non-work devices and accounts can be subpoenaed if there is a good reason to believe you have work materials on your Gmail or personal laptop. Like if in the first review of work e-mails, they find you've e-mailed one work file from your work to your personal Gmail one time or even just have been signed onto your personal Gmail while at work.