less,
“Can anyone prove that today’s razor thin matzos have kernels of unbakec flour that can rise? Has anyome seem a proven case”
Actually there was a case a couple of years ago they put in Ads all over, about Matzohs that was imported from Ukraine (I think) that had flour on top and that all should be careful not to gebruck..(Note -although that too I recall is sort of a chumrah as well, it is only the flour from inside that we are afraid of..the one on top once its baked is not the same issue.)
See below link for an excellent write up how it came about etc.
http://www.hebrewbooks.org/pdfpager.aspx?req=13595&st=&pgnum=134