^ Ya know, your right and I have seen the kinking myself.... But I believe it's limited to certain manufacturers. I've run a few since that don't kink but I have had them kink.
O rings have nothing to do with stretching. Orings keep the rotating parts of the chain clean and dirt free so they last longer. The quality of the chain and it's tolerances are what allow them to stretch.
I do not run oring chains on any 200CC and under 4 strokes, it saps too much power from the engine. Of course it may not amount to allot, but when your trying to beat out all the other 200X's around you, it matters
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country