> Which companies own which IP address blocks is public information.
People are working from home! That's the entire context of this thread! They aren't using corporate IP addresses! And they don't do it when travelling either!
> Conferences are announced; advertised, even.
People travel for other things beside conferences. For example to a meeting or client site.
> That's OK, companies do a fine job publishing employee information all on their own.
Many don't do this.
> What is a benefit you can gain from knowing someone at some IP address opened your email?
I've already listed all these things.
> Can you get that benefit some other way, such as by looking in a phone book or viewing the company's website?
Yes, people not listed in a phone book or the company website.
You're listing exceptions, but they don't apply to everyone. If they don't apply to everyone then you can catch some people.
Try this to help yourself understand - people do in fact use tracking images. Therefore, do you think that maybe there's a benefit to doing this? Otherwise why do you think they do it?
People are working from home! That's the entire context of this thread! They aren't using corporate IP addresses! And they don't do it when travelling either!
> Conferences are announced; advertised, even.
People travel for other things beside conferences. For example to a meeting or client site.
> That's OK, companies do a fine job publishing employee information all on their own.
Many don't do this.
> What is a benefit you can gain from knowing someone at some IP address opened your email?
I've already listed all these things.
> Can you get that benefit some other way, such as by looking in a phone book or viewing the company's website?
Yes, people not listed in a phone book or the company website.
You're listing exceptions, but they don't apply to everyone. If they don't apply to everyone then you can catch some people.
Try this to help yourself understand - people do in fact use tracking images. Therefore, do you think that maybe there's a benefit to doing this? Otherwise why do you think they do it?