Actually many times checkusers run checks of accounts whose edits are stale  For one thing it is simply easier lazier to click the check button and let the system tell me whether there are any results rather than first checking contribution history especially when checking a lot of accounts  For another the checkuser tables include deleted edits and the sending of emails through the specialemail function neither of which shows up in a quick check of contribs although deleted edits would show if I looked at both the live and deleted contrib pages  As far as the oversighted edits Ill cover that in email with Giano