I have had this problem also.
I just opt to not put the nappies through the dryer anymore...
But I am a little worried about other articles of clothing the have snaps such as sleepsacks and pyjamas...
I don't use the dryer very often, but when I do I just have to be careful. Our dryer automatically senses when the clothes are dry and turns off.
My new blog called Inspirationz. Yah!!
Our amazing DS, May 2006
Our sweet DD, August 2008
Our gorgeous DS, September 2010