I think, AOG, this passage from the end of the report is most telling:
“Mid-Devon Council declined to comment further and did not elaborate on who might be confused by the use of correct punctuation.”
So, "Don't ask me to elucidate on the ridiculous statement I've just made. I've said it and that's that and if you think you're going to get a sensible explanation from me, a representative of an organisation that is taking these decisions at public expense, then think again"
So the answer to your question is that anybody who knows about the correct use of apostrophes will not be confused by their use. The issue really is that there are increasing numbers of people who have no grasp of many of the most basic rules of grammar and punctuation and who also have little grasp of simple arithmetic. (Last week a report was published which suggested that one in five adults cannot add together two numbers over a hundred without a calculator).
I find that very strange when we are told that the academic standards achieved by youngsters is now, allegedly, better than it has ever been. Yet vast numbers of them struggle with grammar, punctuation and arithmetic.
The rules for the use of apostrophes are simple. I think I learnt them in less than half a day at primary school. It is clear that such simple instruction now no longer takes place or if it does it is not very accomplished. Of course there are some anomalies which have been mentioned, but that should not consign the entire principle to the dustbin. So, as with many things that become “too difficult”, the answer is to suggest that they are no longer relevant, no longer needed, overcome by evolution or some other some other excuse to explain why children are not taught properly. It is true that apostrophes seldom make huge differences to the meaning of phrases or sentences (although thecorbyloon has shown that they sometimes can). But they are a part of the grammar “package” to which we should all subscribe. They should not be summarily dismissed as no longer needed when the true explanation is “we can’t be bothered to learn about or teach them”.