\newif\if@noproofreadmark \@noproofreadmarkfalse
\def\noproofreadmark{\@noproofreadmarktrue}

\def\addspan#1{%
 \if@noproofreadmark%
   #1%
 \else%
  \textcolor{red}{#1}%
 \fi%
}

\def\delspan#1{%
 \if@noproofreadmark%
  \empty%
 \else%
  {\setjumocolor{red}\Midline{#1}}%
 \fi%
}

\def\delspanx#1{%
 \if@noproofreadmark%
  \empty%
 \else%
  #1%
 \fi%
}

\def\strikemath#1{%
 \if@noproofreadmark%
   \empty%
 \else%
   {\setjumocolor{red}\Midline{{\mbox{$\displaystyle #1$}}}}%
 \fi%
}