Honestly, this may have actually happened, since Kuromorimine is one of the places we never see Yukari invade. :D
Honesty it could happen now with the new leadership not being as entrenched in tradition it would warrant a mission, that or Yukari really wanted some new tank photos
If I’m not mistaken in one of the CD/Audio Dramas, Yukari visits KMM normally, not as spy. I might be wrong. In the series all members of Anko Team go to different schools to visit.