> and then give customer service (via phone/email) the admin/power user abilities to deal with the few special cases that the website cannot handle.

Typically, the problem here is that customer service is unwilling to deal with these special cases, through some combination of:

1. They are too scared to correct the data - e.g. they have been told to follow some poorly-thought-out procedure to the dot and/or they're scared of committing some sort of "fraud" by entering the data sensibly.

2. Although they could handle such cases in their system, the system has to interface with a labyrinth of other systems that can't.

3. They have to use an interface that is essentially the same as the website, with all of its limitations.