If the test is open book, open Internet, that doesn't mean you can ask your friends on Facebook for help, just because Facebook is on the Internet.
I think that the class was likely poorly designed, but that doesn't mean that the students are all in the clear.
That process is completely cut short if you just copy someone else's answer.
The implied intent of the rule is that READ-ONLY NON-INTERACTIVE Internet use was permitted. To today's students, the Internet is a READ-WRITE INTERACTIVE tool, unless explicitly stated otherwise.
Can you quote the rule because in the article it appears that the intent of the rule was that above all you couldn't interact with other students [on the course] to complete the work but as long as you kept to that rule then general internet resources were fine to use?