Sorcha, rangerroger, and sian, every problem you have with your G-string in public is embarrasing -- as is everything you say about it and everything you say to try to "cover" for the double entendre of the previous remark.  To wit:

"Excuse me a minute.  My G-string is loose."
"Oops!  I tightened my G-string too much."
"Always carry extra G-strings with you when you're performing."
"God!  I hate having to change my G-string in the middle of a concert!"
"Why is it always the G-string that breaks?   I think maybe it's because I play so hard there."
or
"Excuse me, Reverend.  It seems I've snapped my G-string again.  Probably because I've stretched it too much with all this bending."
"Ach!  Meine G-Schnur hat wieder entzwei gebrochen!"  (Gebrocht?)
 
 
 
 

Seriously, though, I had a new guitar that kept breaking strings --  G, and especially B and high E.  It broke two Elixir strings within hours of my installing them.  [Elixir did, BTW, as per their excellent warranty, give me a new string and a whole new set of strings for each of the broken strings.]  Then I took a #2 pencil and slathered the graphite over the edge of the saddle before installing any new strings.   After that, the premature string snapping stopped.
 

Jon F., I play very lightly, with fingertips, a relatively lightweight thumbpick, and fingernails, and I do break the thinnest 3 strings relatively often.  But I think it's because I use extra light gauge strings and I don't change them as often as I should.  I almost never break the three lowest strings.  (They just go dead, of course, it I keep them on too long.)

Genie

PS, Folks, remember that there was a time when all cats had good reason to hate classical guitars, violins, cellos, and the like!  ;- )