Why default form class template makes it public ?

Question

I use Visual C# Express 2008 and when I create a new Form it is created as public. From what I know a public class is visible outside the assembly which contains it. I cannot see any reason to make it public; am I missing something ? My attention was captured by that access modifier because in a project I had to cancel that 'public' for a poor design in other classes it used. Just wondering if I did something bad. Thanks Filippo