Why don't languages raise errors on integer overflow by default?

//Returns the sum of the values in the specified list.
private static int sumList(List<int> list)
{
    int sum = 0;
    foreach (int listItem in list)
    {
        sum += listItem;
    }
    return sum;
}

List<int> list = new List<int>();
list.Add(2000000000);
list.Add(2000000000);
int sum = sumList(list);

int main()
{
    uint32_t shipsHeadingInDegrees= 0;

    // Rotate by a bunch of degrees
    shipsHeadingInDegrees+= 0x80000000; // 180 degrees
    shipsHeadingInDegrees+= 0x80000000; // another 180 degrees, overflows
    shipsHeadingInDegrees+= 0x80000000; // another 180 degrees

    // Ships heading now will be 180 degrees
    cout << "Ships Heading Is" << (double(shipsHeadingInDegrees) / double(0xffffffff)) * 360.0 << std::endl;

}