I just don't think that security concerns around protesters were the principal reason Bush's visit to Switzerland was
canceled. He will always encounter significant protests at every public appearance he makes, particularly those outside of the US. However, I don't think that any US government would sit idly by while a former US President was arrested for actions he committed in office that pertain to his duties. Likewise, I don't think that any foreign government friendly to the US would arrest him on such charges, but would rather negotiate things out behind the scenes. So, bearing this all in mind, I think that this is just a diplomatic dance designed to make Bush feel like a pariah -- and I can't say that I am dismayed by that.