Not all author-defined macros are ``bad.'' This used to be the case, but owing to the efforts of AIP's programmers, we are now able to globally expand ``keystroke-saving'' macros.
``Keystroke-saving'' macros are macros
defined via the \def and \newcommand family of commands.
For example, ``\be'' would expand to ``\begin{equation}''
and would be defined in the
beginning of the file as \def\be{\begin{equation}}.
So-called ``bad'' macros are custom macros that effect low-level formatting. It is not necessary to worry about the finer points of typesetting. Your file is being translated into another typesetting language, and no amount of moving and kerning of superscripts and subscripts and creating open-face fonts (for example) will change the way the final printed page looks like.
If you are going to use your own keystroke-saving macros, please
list all of them at the beginning of the file, before the
\begin{document}
line. Do not sprinkle your defs (or redefine the same macros!) throughout
your paper. Again, the macro expander will not work unless all author-defined
macros are present at the beginning of the file.
The macro expander does not support Plain TeX commands at this time.
Do not use \else, \fi, \if, \input, \mathop, \mathrel,
\special. As for LaTeX constructions,
please do not use \newenvironment, \newfont,
\newtheorem, \include.
Do not redefine labels, do not
reset counters, etc.