Sunrise go dayflat (or SMSflat/Dataflat) sounds like a very expensive option at 1CHF a day for data, 1CHF for SMS and 1CHF for data on days when you use them.
They have much better options available:
Normally with pay as you go with Sunrise, all calls are free after the first 3 minutes, so it would cost a max of 1CHF a day anyway.
For internet, you can get a bolt-on of 250MB for 7.50CHF a month, or 1GB for 19CHF a month, and it you use it up before the end of the month, they just reload it again on that day
http://www1.sunrise.ch/Surfing-optio...en_CH-CHF.html
Or, for 34CHF a month you have 500MB, free texts and free calls to landlines/Sunrise mobiles without having a 'contract'
http://www1.sunrise.ch/Surfing-optio...en_CH-CHF.html