I think the JWs will APPEAR to make it look like they are complying. But, we all know what that means.
Yes I agree you will probably still get enthusiastic witnesses surreptitiously writing down details of a good call. If there were fines in place for doing so though it would have to be discouraged at their service meetings. They would have to emphasise the importance of getting permission. This would perhaps be practiced in the service meeting - the new wording could be put into those videos they use now. They did something similar when the magazines went to being free with a donation. People had to get used to saying the new wording. That is quite a good example actually because many JW's refused to use the wording & simply gave the mags away without asking for donations. That could well happen here too, and JW's might not bother asking permission as they are told & write it down anyway.
If the new rules affect the taking of not at homes then that is very disruptive and can't be got around so easily. Its an entire formalised part of their ministry. It'll be interesting to see what happens.