This is not the "chinese whispers effect"; it was groups of monks collectively reciting the same texts. And these were sacred texts, which by that virtue alone would there would be resistance to altering them.
Let's not get into a huff - I never said it was Chinese whispers. I even stated clearly that amongst quality practitioners as these monks and arhants obviously were
that that would be unlikely, "but could occur elsewhere". It was to illustrate that these arguments over whether it was verbatim or not are not sufficient. As far as the written word goes, it is always possible to misspell words etc.
I am trying to make the point that "historical records" are not enough for the serious practitioner. There has to be consistency, integrity, and also it has to be borne out by testing it.
In fact your conviction in the fact that these monks and arhants would have had such reverence that any deviation would be resisted, is an illustration of such reasoning regarding the consistency of these scriptures.
Not all inferences need to be based on direct perception, they just need good reasons.