just copy the bad data, you cant copy bad secotrs… in other words it wont make a new drive develop bad sectors as well, as I think this is what you are asking about
Worst case is any files stored in the bad sectors now may either fail to copy or partially copy leaving you with corrupted files. If that happens results of these files depending on type can vary, such as executables will suffer most and likely not work at all, pictures may have odd blurrs, smudges or distortions, documents might have starnge ascii characters, and video’s might miss segemts or distort and freeze during a scene or range of scene. If the data from these bad sectors fails to copy then you will see errors with recyclic redundancy.
In most cases you can get back over 90% of data unless the drive is really fried.