Board Thread:Support Requests - Getting Started/@comment-24108228-20180206101531/@comment-24108228-20180206131116

There doesn't appear to be a pattern.

Minecraft Wikia, Fallout Wiki, Animal Crossing Wiki - as you'd expect, the larger wikis on mainstream topics have custom namespace searching. Whilst this could be due to them being larger, mainstream topics, some comparatively tiny wikis also have default namespace searching changed, such as both of the Apocalypse Rising wikis (here and here) - they're (fairly old) wikis about a game on Roblox, with 200 and 375 articles respectively.

I haven't a clue how to check if a wiki's got it's own community app or not, but if fixing your default search settings was a side effect of getting a community app (or some other official recognition of importance and quality from Wikia Staff), then you'd expect the Roblox Wiki to have got this before smaller wikis on topics within Roblox itself did.