Originally Posted by salmonsweet

Actually, copyright in detail is tricky, and can differ quite a bit depending on which country you are in.

For instance as a general rule, in European countries copyright exists irrespective of whether or not the creator placed a copyright notice on their work.

I'd say if in doubt, respect another person's creation and assume there may be copyright protection! It's what I want to happen with my own work, so it's what I want to do for others as well. Just another 2c. :-)