Reason for not allowing import twice but allowing reload()

[alien2utoo at gmail.com]

Thanks Chris and Ian,

Your suggested experiments and explanations have really provided some good insights, something Tutorial didn't indicate.

Ian's explanation reminds me of 

#ifndef _HEADER_H_
#define _HEADER_H_
...
#endif  // _HEADER_H_

in C/C++, and I can draw parallels to why subsequent attempts to import same module shouldn't result in flagging an error, and need for multiple imports to refer to same information.