A closet with a panel WILL be filled with junk. An electrical room that can only be used for electrical is only deep enough for the panel.
Residential inspectors know this, but they cannot really enforce the clear space rules. It is a Bill of Rights right to protection from unreasonable search by any governmental agency, which includes the local building official.
Until George W. Bush takes away all our rights to privacy, there will be junk stored in front of electrical panels.