On Jul 4, 2014 7:55 AM, "Frédéric Schütz" schutz@mathgen.ch wrote:
Their main worry seems to be "how do we make sure that people do not use the pictures in a way we're not happy with"
That question qualifies as "frequently asked"; my usual answer is to the effect that "You cannot - but anyone who is going to use them maliciously is not going to worry about niceties like copyright. The people whose activities you limit by applying a restrictive license are the good guys - and yourselves."