I've encountered users with several questions asked, all (or most) of them answered, but none accepted. Generally, they have few rep points (<100), so it's easy to mistake them for users who have just signed up; is there a quick way to identify such users (other than taking a look at their profile), who are not really newcomers to the site, but have not been accepting any answers?
What is meta?
- Any Stack Exchange user can ask a question
- The community provides support, votes on ideas, and reports bugs
- Your voice helps shape the way Stack Exchange operates
The only users that don't display accept rate are those with less than 4 questions under their belt. So, really, you're getting the accurate information for the majority of users.
If you want to look more precisely than that, it isn't too much of a detour to look at their profile. It's often more telling (for example users may also have a lot of downvotes). Otherwise, consider that it's frustrating to not get the checkmark, but you've done your duty in terms of answering the question for future users, plus you can still get a healthy number of upvotes from other people.
If anyone finds a way to quickly identify users with 0% accept rate, please post it here so we can have it removed immediately. The last thing I want to do right now is delete 30,000 more "Work on your accept rate." comments.