I like a dot before my section-entry in the table of contents. When I apply the \setcounter{secnumdepth}{-1} line in the code below the dot also disappears.
\documentclass[11pt,landscape]{article}
\usepackage[dutch]{babel}
\usepackage{lipsum}
\usepackage{tocloft}
% \setcounter{secnumdepth}{-1} % this line causes the trouble. removes the
% sectionnumber (which is good) but also removes
% the dot (which is not)..
\cftpagenumbersoff{section}
\renewcommand{\cftsecindent}{15mm}
\renewcommand{\cftsecaftersnumb}{$\cdot$ }
\begin{document}
\tableofcontents
\section[Welkom]{Welkom en tot ziens}
\lipsum[1]
\end{document}