Suppose a website contains 20 pages & having similar type of error in most pages.Tester checked one page & posted the bug in a bugtracking system including that this bug remains in most pages but developer only debugged one page (the location Tester had written). Now who is responsible to check other pages Developer or Tester ?
Yes, it is responsibilty of the tester to identify the bug
While Posting bugs we have to clearly specify that this bug is repeated in other screen also.
By mistake you have posted a bug saying that error is displayed in a single page ....Then there is a thing called Defect discussion where the nature of the bug is discussed with the development team by EOD... where the development may come to know the nature of the bug...