Even if python.exe starts normally, py.test for example uses os.dup2() to redirect the file descriptors 1 and 2 to temporary files. sys.stdout.fileno() is still 1, the STD_OUTPUT_HANDLE did not change, but normal print() now goes to a file; but the proposed script won't detect this and will write to the console...
Somehow we should extract the file handle from the file descriptor, with a call to _get_osfhandle() for example.