When the fonts are not installed, using apc.mpl.setup results in an avalanche of warnings like this:
findfont: Generic family 'sans-serif' not found because none of the following families were found: Suisse Int'l
This warning is confusing because I thought there should always be a "sans-serif" fallback font. In any case, we should try to suppress these warnings, if we can, just because they are an unpleasant user experience in a notebook context.