This is indeed a problem, I propose we make a note of it in wikiproject Thailand so that people will be aware of this issue.
I was introduced to Dietmar who created this tool http://regio-osm.de/hausnummerauswertung/ I think it’s a nifty way of bypassing some of the copyright issues by using potentially copyrighted sources as a guide but verifying and adding information independently. It is presently used for housenumbers but I don’t see why it cannot be adapted for a range of different applications such as geoname village names verification.
I think this tool + mapillary could be a winning combo in getting information online.
Please notify people who are trying to use this as a data-source. At least they had been caring enough to specify this source. So it’s easy to clean up. Worse would be the copycat action omitting the source. If someone could detect a copy action it might force us to redact large quantities of data.
I’ll forwarding a link to this discussion to the data working group and ask for advice. Simply deleting would not remove the data. It would require redaction to remove it from the history as well.
Maybe the take-over was in such a small scale that no action is needed at all because of an insignificant amount.