Been catching snakes like this since if was 15 or so, never 4 at a time and mostly browns but never been close to being bitten. They can climb up their own body and bite but as long as you keep them at arms distance and shake them if they climb you will be fine.
The only reason not to carry them upside down like this is so that it doesn't dislocate the spine and it causes a lot of discomfort to the snake (or so ive been told)

Music? who is this

There are plenty of skilled shearers around the world, while the UK has a shortage due to Visa issues Aus and NZ have plenty. As for Sageminds comment on how he could sheer a sheep faster i would like to see that, and the sheep would not have a heart attack.
I dont think this machine would ever replace a human due to the fact it would take longer to strap it down then to shear the sheep. The machine worked quite well though apart from the un-natural position the sheep was in it was shorn very cleany, not many cuts and only a few tuffs of wool left