Have you tried using quality brand of batteries? Never happened to me. IMHO not a design flaw.
Duracell and Energizer not quality brands?
There is a lip on the inside of the battery tube caused by a narrowing of the tube about 2 cm down from the entrance. If a battery label starts to come off, the battery is slightly fat or damaged (particularly on the end where the cover wraps over the terminal) it can become caught on the lip where it narrows. It most definitely is a design flaw. It's not entirely clear to me what the purpose of the narrowing is, even if they -
1. Enlarged the tube diameter at the end by 1 mm
2. Kept the same diameter all the way down.
3. Changed the angle of the narrowing step (which seems to be about 45 degrees), they would avoid these issues.
BTW: it has only happened to me once too. But once may be a disaster in the field when you are trying to change batteries on an important gig.
digifish