It's all about the integrity of their characters. They [Marvel] care so much about the loyalty and integrity of each and every character and all of their stories. They trust and love their readership. They're the ones who have invested in these stories.
A lawyer once told a jury that the person his client stood accused of having killed was about to walk through the courtroom door. When the jurors looked startled, the lawyer asserted that if those jurors had wondered, even for one second that the victim might appear, that belief constituted enough reasonable doubt for them to find his client innocent.