The CHF has been encountering a perfect storm over the last two years with all factors pointing in its favour; the fact that all the other major currencies have major issues to contend with, the Eastern European loan saga, general risk aversion after the GFC and most recently, the flow of money out of Greek banks (and into Swiss ones in many cases).
EUR/CHF should see some renewed volatility after the Greek austerity vote; a yes vote will ease the worries and may lead to some short-covering but a no vote could lead to a stampede of deposits out of Greek banks. The latter will have a big impact on EUR/CHF and it’s little wonder that the SNB is worried.