I started mapping at a mapathon in iD not that long ago, and it was made very clear by the instructors to “Always” if not “as much as possible” use the “squaring buildings” options in iD for the buildings mapped. It was also explained why this squaring was so important.

In my opinion, it’s just how you instruct new mappers. If the new people follow the instructions of experienced mappers to the letter, all will be OK for validation?

I did my first tries in JOSM recently, but will need to look at much more tutorials first, before I can actually use the program correctly. There are so much options there, you get a bit lost at first.

What iD could use is an option that points you to possible inconsistencies in your mapping, and maybe also suggests you how to solve them? Are people who make errors in mapping given feedback by validators, that might be handy?