Curiously enough I had a conversation with fatshark about this very theme at the SNHBS conference last weekend.
The thing about placing them the right way up and the blocked spiracles blah blah blah seems to be something that started within Bibba. It's likely in one of the Beo Cooper or Mobus books but is just another old wives tale which gets endlessly propagated. They usually come off the paintbrush the same way up anyway.
In my experience larvae are quite resilient and are most easily damaged by drying out.
Having said that I have grafted into cell cups at one apiary and filled a tupperware container with them then cycled 6 miles to another apiary with the larvae jiggling about in the Tupperware. Most of them got started when placed in the cell raiser colony. The ancient bicycle in question was not equipped with any James Bond style self generating high humidity system or any other defense systems associated with a perilous activity such as moving larvae from one place to another.