i often see a "Guest #####, or Anonymous##### post, and only recently understood that those are posts made by former members before they left PC.

it is possible, i actually spend some time doing it, (to see who left), tracking down the acronym. also, if a person suspended their own account, for a while, it will still be accessible to look at, but not to post on. if they have been terminated by staff, their whole profile page vanishes.

if i err, i hope to be corrected~