I think that many of the admins try to check recently posted comments, so the fact that you post on an old unidentified or a recent one does not change much, the comment has in both cases chances to be seen.

Until last summer I had time to check all comments, so usually I was trying to take in account all what was missed by other admins (though that often I couldn't really know what was correct or not). Unfortunately nowadays I can't do that anymore. Other admins try to check what is posted, but it is not possible to check everything.

As Night Cub said, indeed we do not always know if new contributors are reliable or not, if it is out of our expertise area. So sometimes we wait that someone else with more knowledge than us confirms what has been posted. Unfortunately for bikes we have a lack of experts, so when someone new arrives his comment can't easily be checked.