I've only ever gotten in two packages from Yann, 
but they were both packaged the same way - in 
shallow cardboard boxes with the cels wrapped up 
in a layer of bubblewrap.

Both boxes have also arrived with holes gouged in 
them. But the squishy, roomy inside has kept the 
cels themselves from being damaged. :)

Plate armoured packaging is good - but sometimes 
light and springy works just as well. :)