I don’t think we should exclude rare words, on the contrary.
When I’m not sure how to pronounce a word I’m not familiar with, either I pass the sentence, or I try to guess the pronuncation. In some instances I also looked for the pronunciation in Wiktionary, but it requires to know the International Phonetic Alphabet.
As for short names, I guess that “RTE” is an acronym; I don’t know how acronyms should be dealt with, but my guess is that we should simply read the letters one by one when we come across one.
That being said, I think that a button to report problematic sentences may be a good idea; but I think it requires to display some recommandations about what kind of sentences should be reported (e.g. spelling mistakes).