Hello,

There is sadly no good system to mark some changes as temporary.  If you are familiar with the place, the best way is if you can remember to edit the map after the works are finished.

For the note tag, leaving a public note is possible (but I wouldn’t recommend this; the note system has been abused so much that we are currently overwhelmed with thousands of open notes asking for our attention).  I was merely talking about the note *tag* attached to objects, such as roads.  This is a free text that can be added to any object, and is aimed at fellow contributors.  We can easily query the database to get all the streets with a note.

In the iD editor, there is a text box with "Add field" and you can look for "Note".  Here is an example:
https://img.multimob.be/1KIktRzh/o4yXfST5.jpg