I pulled out of a high speed dive one time with a trainer (no throttle, just a lot of gravity!) and my two wing tips kissed each other. Shortly thereafter, my plane kissed the ground (very hard!). I learned not to do this anymore. I don't do any abrupt pull-outs from dives with any of my planes! I have a contender that I built from a kit. It has a one piece wing--the spar is continuous, and I won't even do it with that plane, for fear of seeing the wing fold up again. And, Pulling out inverted? An even faster way to fold a wing. Bottom line--don't do this maneuver. Sooner or later you will find out the hard way!
And, putting rubber bands in talcum powder will dry the oil out of them, but why? I can buy a 1/4 pound box for 1.35 at the LHS--is that worth a plane? It's just not worth it to me to reuse them. When I'm done for the day, I take a knife and cut them off, so I'm not tempted to use them again (and, I'm a little lazy!). Then again, I don't fly a plane with rubber bands much anymore.