Well, it's tough to say whether the cover is badly designed or not, given that it was not strictly speaking designed for a cybook. Maybe the two devices are slightly different.
JapaG, don't be sorry!

You are quite happy with the case and that's what matters. Different people have different habits and there's no perfect thing for everybody. My concern in posting here was to warn other people about what I didn't like, not to complain about your advice.
Anyway I think I'll try and cut it a bit this week-end, to see if I can prevent the button presses. I'll let you all know how it turns out.