As many as a fifth of all iPhone 4 owners have been hit by the iPhone 4's "death grip" issue in some form but could be happy with Apple's case fix, ChangeWave said in a study today. About 21 percent of owners responding either thought it was "somewhat of a problem" or a "very big" problem, but 73 percent of the group was either very or somewhat satisfied with getting a free case to address it. The majority, 64 percent, either didn't think it was an issue or hadn't noticed it in practice.