I love making lists within Google Maps. Adding places to my ‘Starred places’ or ‘Favourites’ or to some custom lists I have.
However, should a place on that list be removed from Google Maps, you then end up with a pin which has the lat/lon co-ordinates and nothing else. This ties in a little to my previous feature request, but surely a local private copy can be retained.
I have so many pins with just co-ordinates and no longer know what it was I saved. In many cases, it is where someone has removed a pin for a place that does still exist.
I agree this is annoying, but if a place never existed then I understand Google Maps does not bother to keep a record of it.
Again, what is needed is probably better education of Local Guides so we don’t use the “Never existed option” and instead use “Temporarily or Permanently closed” options. Both of these can be reversed and keep the record intact.
Agree on the education point. Perhaps there should be an online Local Guides course you have to complete before you can contribute 
I have been advocating for better guidelines and some proper education for a long time. So I couldn’t agree more.
But it is a balance not to make it too hard or too easy to make edits. Google is very well aware of this.