>All of which I hope goes to show that these choices are a matter of taste, not absolute rules
Throughout this exchange I have avoided calling these rules and used convention instead, and that is what punctuation use is. Conventions are easy to break but you should have a good reason to do so if you want something to be readable and you must be consistent in your choices. I have tried to emphasize this throughout and I have repeated it many times, consistency of use is what really matters, punctuation marks are pretty much sign posts for the reader and as long as they remain consistent in their use and are well formed than most readers will have no issues figuring out any use.
Imagine if a town decided one day that they could save some money on removing a no longer needed stop sign by simply agreeing that it is not a stop sign, it is a small town and they can just pass the word that the stop sign on third is now a 30mph sign. This works quite well and save some money so now the town continues with this and starts changing the meaning of other signs. It is not difficult to see why this would be troublesome, eventually people will get confused and no one from out of town will have a clue. Thankfully our governments are consistent with their signs and a stop sign is a stop sign.