PVC is fine for a few bows a year, could you imagine the cost a big bowyer would have if he shipped 100's of bows a year in PVC, I use a 4x4 telescopic box with bubble wrap and with over 500 bows shipped by usps I had 2 tips bust out of the box (with no damage) and one broken one. That one was paid within a couple weeks by USPS.
I used UPS before USPS, now they are hard on bows! It sucks when it happens, lucky for us it doesnt happen to often.
That picture is funny Bjorn, I once had a guy send me a bow he bought used for a refinish, he wrapped it in tyvek! It made it ok, but I told him he probably shouldnt do that anymore.