Looking at these one at a time:
https://www.openstreetmap.org/changeset/118332979 was two years ago and the user has not been active since. Likely the level of training that this new user was given by whoever asked them to edit OSM was inadequate, but as it was two years ago there is little we can do now.
https://www.openstreetmap.org/user/MartyTheZebra was similar, last edit 2 years ago.
https://www.openstreetmap.org/user/JClaireD was similar, last edit 2 years ago.
https://www.openstreetmap.org/user/Jerome%20Deloix was similar, last edit 3 years ago.
https://www.openstreetmap.org/user/mairfan99 was similar, last edit 4 years ago.
What can we do as a community in such case? How can we mitigate this?
With historical data such as that listed above, all we can do as a community is tidy up afterwards. However, with more current problems, I’d suggest:
- Comment on new mappers’ changesets and do as suggested here. All new mappers make mistakes, so always try and stay positive - explain what they need to do to avoid creating future issues, and don’t use a changeset comment tool that marks things as “BAD”.
- Try and find out who’s supposed to be teaching them what to do and approach that person with how they can improve their teaching.**
- Look at the tasks that new mappers are being given to do and if the instructions are poor quality or wrong, contact the person who created the task on the tasking manager. .
- If communication fails at any point email the DWG via data@openstreetmap.org so that we can help bring problems to people’s attention. The tasking manager userid will match the OSM userid; we can and have blocked HOT task creators because they could not be bothered to respond to other people about the poor quality work they were causing new mappers to do.
There are various ways that you you could find potentially iffy edits - changesets with lots of unanswered comments and changesets with no actual words but only hashtag gibberish are a couple of obvious ones. Massive changesets are another; and you also mentioned changesets with a descripton that does not match the location.
** this can be tricky and often is a completely different person to whoever created e.g. a HOT tasking manager task.