Pinyin without tone marks is no more wrong than Hebrew without vowel pointing. On the other hand, Pinyin without proper word parsing is just plain wrong. The very first rule of Pinyin orthography is that words, not syllables, are the basic units of writing in Pinyin.

Even by the PRC’s official but drastically inflated literacy levels, more than one million people in Shanghai are illiterate. So, yes, there are many, many people in Shanghai who can’t read — much less write! — enough characters to qualify as literate.

When I wrote of the desirability of having romanized Shanghainese displayed, this wasn’t out of the notion that most people would know how to read it. (Of course they wouldn’t. Other than when it comes to English and other foreign languages, the Chinese government works to repress writing in anything other than Mandarin as written in Hanzi. But acquiring literacy in such a romanized script would take little time or effort.) Rather, what I was addressing was simply the notion that the native language (not “dialect”) of the people of a place should receive no less recognition than other languages imposed upon the people. I consider this a basic human right.

For a little on this from the perspective of Taiwan, see How to Forget Your Mother Tongue and Remember Your National Language.

Do you actually think there are many speakers of Shanghai dialect who can’t read the characters? If so, do you think they read romanized Shanghaihua?