"will it stop the unintentional sign-ups?"
Nobody will ever know. I'm sure that lots of people will still say they had no intention of signing up, in the same way that lots of people say they aren't aware of the software licences they accept when installing programs.
You can lead a horse to water, etc.
We should at least take some comfort from the fact that we, the people in this forum, have been instrumental in bringing about this change.