Is it a good thing or a bad thing for the senders of email to know that the receipients are deleting without reading?

This is part of a conversation where the 2 people involved were in different places: “I can see he was deleting my email, so I coudn’t communicate with him…” (the person stole his cellphone and he was trying to get it back, it was in the news)
I find it is a private matter what a recipient is deleting them or not for security reasons. That would set an mentally unwell ex, a stalker off, no?