I would be interested in seeing the statistics being used by the Swiss Government to support such a proposal.
Intuitively, to me at least, the idea for "Games as a cause for violence" is not based on rational thought.
A more likley explaination is "ape brain as a cause for violence", preceeded by "selfish gene as a cause for violence" coupled with "lack of self control" as a catalyst.
Simply speaking, to make a theory that cites any single activity a cause of violence is going to be woefully inadequate at describing reality.
And the idea that it is a valid approach to seek the removal of the rights of an individual to persue an activity (like reading, or making films, or playing video games), activities
which primarily deal with the imagination, and the "internal", well that is abhorrent to me personally.
I would add, that it is my belief, that it is not really the responsibilty of government to protect me from the ideas of others per se, but it for those institutions to protect me from
any practical application of ideas that threaten my safety.
Again, the correlation between video games and violence is overshadowed by other factors (such as population density coupled with poverty say [conjecture] ), significantly enough I would argue, so that the argument violent video games are a practical threat, is rediculous.
Anyways, you get my point ;)