Interesting point along this thread is the use of ear defenders. After one particularly scary situation I was in I stopped wearing ear defenders on the ramp.
Engineers were ground running and did not have the strobe on. There were other aircraft running in the vicinity and I had on a pair of very good ear defenders. Cocooned in my deaf little world feeling safe and not very alert I only noticed the engines were running when the wind suddenly picked up to a frightening gale and became very warm. I had walked behind a running engine- god knows what would have happened if I had walked in front of it.
The moral of this story is I would much rather be deaf later on in life than chopped into tiny little pieces on an aircraft ramp!!
Needless to say I had a little chat with the safety man afterwards who had missed the whole entire event for some reason. He doesn't miss much now.