Yes and no. Some cracks we internal but obvious is you knew where to look (I did thanks to this forum) and the othrs occur on the face of the stove and should be noticed by the average user that cleans his stove once a year. You can look up in this thread for pictures.
As you said, some are obvious, others not so much. Most stove owners are probably not as diligent with their inspections and/or cleaning. I didn't even see the one crack on the firebox door rim of my stove, until I saw it in a picture I took of the firebox. The camera flash brought out the detail of the hairline crack. So good lighting is important when inspecting your stove.