So far, there's only one way to differentiate posts listed in the flag queue. Between questions and answers, questions show the user-card in blue (as it always has) and answers have an additional
"asked [date]" shown.
It also shows us a little information about the post owner such as when they first joined but it's not enough. There should be a distinction between registered and unregistered users. It would help knowing whether they are registered or not as we could understand their mindset when they submit their posts without having to go and check their profile. And with the crackdown on Stack Overflow on requiring users to be registered to ask questions, many unregistered user are now using answers inappropriately more frequently than before adding even more work for those who checks up on the flag queue.
Technically they haven't actually joined yet, only participated on the site and it's misleading. So I propose that to identify them easier, the join line should be displayed as:
unregistered since [date] (or
participated since [date] or other) for unregistered users.
Please make it even more easier to identify them.
Note: This is not a request to identify unregistered users everywhere, only in the flag queue.