This would make doing reports MUCH easier, especially if someone leaves right after doing something against the rules and you can't catch his steamID for a report. Technically you can get someone's steamID from a demo by converting the demo to a replay, but less experienced players in demo editing don't know how to do that. It would help the overall server experience.
I've seen a few servers that do this. For the most part however, copy and paste from console or chat isn't super reliable and it can be ugly to look at and clutter chat. Though it sounds silly and time consuming, blackwonder could implement a server log on the website, where you can view all servers, and view the last 5-10 minutes of join/leave history from the server. There you could display steam IDs (or even a link to steam profiles while you're at it but that's redundant and would only help first time reporters).
EDIT: Didn't read what
@Lucas said, so I guess my suggestion already exists. But I support the idea of adding steam IDs to the dialog.
If you go to steam and look on you friends list and go to recently played with,
it looks like this
https://gyazo.com/9b5608044d68a4a9d15d89294d70f6e7
you can use a website that takes the steam profile URL and turns it into thier ID. I use
https://steamid.io/
This is a very inaccurate way of doing it. Most of the time when it's 'current players' it only shows about 5-6 people (from my experience) on the server you're currently on, sometimes even people who recently left. The 'recently played with' tab also doesn't seem to accurately display it, as (from my experience) I could have just played a server, but it only shows people from a server I played 3 days ago.
