For me this seems to be a non-issue, but, I guess some cameras have serious problems in this regard.
I just returned from a day at the beach photographing a wedding client of 8 years ago and their 2yr old daughter at the same spot we did their engagement portrait.
I used the Mamiya 645e...a wonderfully user-friendly unit!
When I got home I had one full roll left in the camera that had not been exposed. I removed it in the darkroom and felt for the bend areas, since it was left in the camera for over an hour. The bend areas could be felt distinctly.
The bend areas were exactly at the edges of the frame where the space is between frames. Since all of the Mamiya 645 units use the same film inserts, all the way back to the original M645, I would suspect they all behave the same. The 645AF may use different inserts (though I doubt it), but the Super and Pro do use the same inserts as the 645e and earlier models.
The bend is between frames. I have a full length processed roll in front of me now, and the spacing between frames is quite wide: 8 to 10mm (1cm). This corresponds to the area spacing on the rollers on the inserts between image frames.
This is consistent throughout the roll.
Also, I have not had any problem of this nature with the two Hasselblads and two RB67 units I previously owned.
Oliver, are you using a Mamiya 645AF for your test? Also, I thought the 645AFD was the digital (no film) unit?
What camera did you use for your newspaper test?
I can not imagine any company making a high grade Pro unit where the bend is centered in the middle of the frame. That's both insane and irresponsible, not to mention stupidly poor engineering!
What about Bronica and Pentax and Rollei SLR MF cameras? Do these have similar problems?
I'm not concerned with using my Mamiya 645e, even if I leave the film in for an extended time, since it seems evident that these units are expertly designed to place the bend between frames and not affect the image area, based on my tests and measurements.