• no falls = no pain and less potential risk.
  however, my moto is if you aren't taking whippers you aren't trying hard enough, lol.
• When catching the line... using your armpits may save you from a whipper, but holy crap its so painful i do not think its even worth it.
  The best way to catch the line is to grab it with both hands, and hook your feet as you fall. There is only one flaw to this strategy
• if you do fall, and you try to catch the line, and miss... you end up plummeting straight down... ouch. thats always is an ouch.
  when you let your knees buckle, bend down only to miss the line, and fall straight down directly below the line; I think those can be the worst whippers. I have seen someone fall straight down with the line in between her legs (another huge NONO) and flip head over heels around 5 times. Think of an utterly out of control cart wheel. No fun.
• the last thing to avoid is NOT trying a highline because your scared of falling. Falling is scary, and you have to get used to it. You can't pick up a guitar and just start playing little wing, it doesn't work like that. You need to practice walking, and you need to practice falling. The worst thing you can do is NOT get out there and try.

But remember to be safe, and always double check your double checkings.