Wiggle test? That's a new one....
Being an engineer in a past life, I don't do any wiggling before flight (appart from having a nervous one in the toilet b4 I piss in the pots or light the fires). Although if it's a light aircraft I do seriously shake and pull the hell out of everything attached to the airframe that's susseptable to failure.
I assume the wing had fuel in it, wouldn't the weight of the wing and fuel collapsed the strut if the bolt was removed? Maybe the fairing and screws carried the weight??? Very interesting.