Vacuum switching valve

My wife has taken the Avalon in for oil changes and this has happened twice. After getting the car home I always check that they put in the proper fill of oil and check that her battery wasn't stolen as this happened before. Each of the last 2 times I checked under the hood I found that the cable going to the Vacuum switching valve was disconnected.
Can this harm anything if left off? Why would anyone disconnect this cable just for an oil change?

If this is disconnected it will set a code P0446. There is no reason to disconnect during oil change. Considering your history (assuming this is the same store) it is time to find an honest shop???