pwillard:
If you want to use YOUR approach, with switching... this may work. (see drawing) Without ground, the servo won't run. (while simple, it's not really good practice though) See if you get what you want though.
Not good practice? It'll burn out the Arduino pins - don't do this, its trying to power the servo's via the ARduino signal lines!
At the very least switch the power on the high side to the servos and use protection resistors inline with the signal lines (4k7 perhaps).