This is not typically done to prevent blowing the fuse in the car. Indeed, it would often be preferable to blow the car's fuse as it's usually easier to get at to replace. No, this is usually done so that the added wiring can be run at a lower maximum amperage. It's safest to fuse each run at just above the maximum amperage that run could consume. You don't want to add wiring for a 2A camera connected directly to the car's 20A run, so you put a 2A fuse inline with the camera. This is particularly important if the wire gauges differ.
In any case, if the wires got crossed at where he tapped the 12V connector or prior to the camera's ~2A fuse, it could have blown the car's fuse.
I don't recall the fuse position you need, but it's in the frunk. Pull up the owner's manual on the 17" display. It has an extensive listing of the fuse locations and their purpose with a handy graphic. If you don't have a low-amp fuse in line with the camera, make sure you put one in.