Hello pmbrown2,

They would have to turn it on to verify the fan spins, however, I doubt they would need to log into your computer. You could always Encrypt your data to be safe, click or tap here to see how you can encrypt your device.

Be sure you have a complete backup if you go this route, I have seen manufacturers factory default the Operating System when they are repairing a laptop.

You can tap or click here for a disassembly video if you wish to remove your SATA SSD / M.2 SSD before shipping out for repair.