The GDPR affects, what? 10% of the worldwide JW population? 15% tops?
Correct, so that's about 1.5 millions JW.
And if we look what may come in the U.S., soon it will affect around 30% of all JW and especially WHQ: https://www.zdnet.com/article/gdpr-usa-microsoft-says-us-should-match-the-eus-digital-privacy-law/
To order JWs to stop taking notes is a radical step and without a very good reason, it would make lots of JW upset. But this way, when you are forced to change this fundamental things by law, JW will adapt and G.B. can turn it to their advantage.