I wish the documentation was more clear as to whether the arg_separator.output character is automatically encoded when PHP outputs it. In other words, is "&" valid or do I need to specify the encoded character "&"? It would make sense to specify only "&" and hope that it is encoded as needed. That way the value could be read by other functions and encoded only when output to HTML, rather than having to test whether it is already encoded and decode it when necessary (for header redirection for example)