Hmmmm....maybe my magnesium shavings are different? but just two weeks ago with the youngest daughter in learning mode, we easily made a long burning filings pile...since they were 'cupped' in a leaf they couldnt blow away-so maybe increase the size of the pile.
As far as a neck survival kit I couldn't wear one...the irony is that I'm wearing a neck knife right now and had forgotten it was there until reading this thread!