Conditional initialization in switch

Why does this code fragment run fine

void foo(int i)
{
    switch(i) {
    case 1:
    {
        X x1;
        break;
    }
    case 2:
        X x2;
        break;
    }
}

whereas the following gives compilation error (initialization of 'x1' is skipped by 'case' label)?

void foo(int i)
{
    switch(i) {
    case 1:
        X x1;
        break;
    case 2:
        X x2;
        break;
    }
}

I understand that using braces introduces a new scope, hence storage will not be allocated for x1 till we hit its opening brace. But x2 is still initialized inside a case label without enclosing braces. Should this not be an error too?

I think initialization of x2 can be conditionally skipped in both the code fragments