Here is a quote directly from our Customer who has brought this issue to us, using IGNET:
"Links with the mailto: prefix don't seem to be part of the content retrieved by GetContent(), and as such they remain in the final page object. Possibly other link components as well. This results in the problem that when a customer uses the software to redact sensitive information, such as a citizens personal info, some of it might still remain in the final redacted file."
The issue they are facing is when redacting mailto links, they can mouse over the black square and still click through it
This is not ideal as this content is supposed to be redacted, the invisible link to the email address remains on the page