C++: Return std::string reference from stack memory

I will start by saying I've read this topic: C++ Return reference / stack memory. But there, the question was with an std::vector<int> as object-type. But I though the behavior of std::string was different. Wasn't this class especially made for using strings without having to worry about memory-leaks and wrong usage of memory?

So, I already know this is wrong:

std::vector<t> &function()
{
    vector<t> v;
    return v;
}

But is this wrong as well?

std::string &function()
{
    string s = "Faz";
    s += "Far";
    s += "Boo";
    return s;
}

Thanks

Extra question (EDIT): So, am I correct when I say returning (by value) an std::string doesn't copy the char sequence, only a pointer to the char * array and an size_t for the length?

If this statement is correct, is this the valid way to create a deep copy of a string (to avoid manipulating two strings at once)?

string orig = "Baz";
string copy = string(orig);