The current method of detection of NFCCheckBot is as follows, it checks:
- if there are wikilinks pointing directly back to the article where the image is displayed.
- whether the wikilinks which point back to the articles redirect to the correct article (which means, that the article was likely moved and leaving a redirect behind.
- whether the exact string of the name of the article is contained within the image description page.
- whether the wikilinks point to disambiguation pages - if so, it checks whether the disambiguation page is linking to the correct article, or whether the links on the disambiguation page are redirect which point to the correct article.
If none of these situations is met, NFCCheckBot will flag the article as having images which likely do not have a proper fair-use rationale.
This all does not mean that there is no rationale - in any case, if there is a rationale, it is better to correct it so it does note the correct article (generally it is best to fix the rationale on the image description page in such a way, that the rationale has a working Wikilink to the article it is used on - this makes sure that the link is typed correctly (otherwise it will be a redlink).