Show your emails have been read?

Hello, I don't know if this has been covered before, I didn't see anything in a quick search..

Colnect has a function on their site where a person can see if their outgoing emails have been at least opened, if not actually read. Has Numista considered this before and rejected it, or never tried yet?
I find this would help if a person is caught in a stalled exchange where emails asking about the state of the exchange are going unanswered and more time goes by. (Okay, yes, that is presently me waiting three weeks since last communication..)
If a person could see that the emails have been unopened (or using another possible function - I can see the person hasn't even logged in for a while), that person can at least come to a plausible conclusion that the other trade partner is just busy or on vacation, etc etc. Right now, I can't come to any conclusion, and since the coins I could receive are hard to find all in one place, I don't really want to give up. If I could see that the other person had logged in and/or opened my emails and I'm still not getting answers - the direction of the trade is pretty clear.

This feature is already in Numista, not for everyone easy to spot but it is there .

top (darker) - unread
bottom(faded out) - read

Perfect! I see it now, and I do see that the person hasn't even read any of the emails in the past three weeks. Like I said, it certainly changes things! Now, the second part, how about seeing when a person last logged in? Or is that regarded as a privacy issue?

That feels like a privacy issue to me. I'd much rather my presence be known by my activity than by my logins.

It can be annoying when somebody you're trying to swap with stops replying, but I think monitored presence or enforced communication would hurt the community.

I use the ratings to get a sense of whether a person has been active in recent months.

That has been discussed on the French side:
https://fr.numista.com/forum/topic56511.html

The latest idea was an "inactive" status, which would show that someone has not logged in for a definite number of months but not the date of last login.