The side stand switch when the sidestand is up, will place a low signal to a portion of the ECU that then tells the bike that it is safe to engage a gear and move off. By placing a hidden switch in the line, you are preventing this signal getting to the ECU.
End result?? Park in neutral, with engine running, turn switch and walk away. Bad guy sees bike, jumps on, puts up side stand, selects first and engine stops. Engine will not start again.
Not a bad result for a few dollars and a little time.