What Would Happen if power was plugged into the Data Port on the Device.

If they were to mistakenly plug the power into the data port of the device, would this ruin the device, or does the device have protection to keep this from damaging the device?

No, the device protects itself from receiving power on the wrong port, so that wouldn't damage the device.

The worst that might happen is the user would be confused. If you plug a computer's USB port to the Voyager's power port, the device will still turn on because computers' USB power ports output power, too. So they'll see the TinyPilot turn on, and if they visit the web interface, they'll see the target computer's video output, but they won't be able to move the mouse because the Voyager's data port isn't connected to the computer. But if they just switch the cables, it will work and won't harm the device.

I did this by accident, and the TinyPilot still worked fine afterwards. But I would not recomment it :-)