I did not have special Switzerland adapters. My adapter kit has 2 Europe adapters, one with 2 thicker pins, one with 2 thinner pins. I took both and would have used one of them at Hotel Stechelberg, but I definitely do not have one with a 3rd prong. I charged my phone every night and did not encounter a problem. I actually couldn't remember, so I just went and pulled out my adapters to see. The kit I got was either from Kmart or Bed Bath and Beyond and has about 6 different adapters. I have used the European ones and the one for the UK.
On the other hand, the adapter is light and I would put it in whatever bag you are using to contain your adapters and cords and take it with you.