I can think of one good reason why schools probably don't teach hand swinging these days.
I N S U R A N C E!
What does the aircraft manufacturer's (in this case Cessna) handbook say?
Where does it appear in the current CASA day VFR syllabus?
How many flying schools actually have an approved procedure in their training syllabus?
The list is endless.
We've all done it and in most cases successfully and without incident because we took smart precautions such as wheel chocks, pilot at the controls etc. Sadly, for this poor sod he appeared to have neglected even the most basic considerations and I would like to be proved wrong but I'll bet, his insurance company is going to wipe their hands of him and he is going to be hung out to dry.