I'd be curious to know if anyone has ever successfully auto-downloaded an OA patch and I'd be more curious to know how this could ever been happened
I have
I never even noticed the check because it only applies to UDP downloads. HTTP-redirect is not affected.
In addition the code that tells the client what to look for is hardcoded to only look for id packs in baseq3 (ignoring the BASEGAME defined) and missionpack. The missionpack folder might be affected this.
The result is that openarena can reference to an external location where the client can autodownload from.
EDIT: In addition it might be that the filename must not have anything added like: pak2-players != pak2