I think the question should be... how long before we find out that the bOrg is logging and tracking IP's of all JW.org and JW App users?
Elders & MS's already log into JW.org so they already no the IP's of a large amount of their elders and MS's, CO's etc.
All this internet history is certainly at least logged if not tracked. One day soon we will here about someone getting caught and DF'd for apostasy due to IP tracking.
The day will come
I've thought about this before but don't think the end user risk is that high. In general people's IP addresses do change pretty regularly and since people use the internet out and about I don't see a big risk overall.
I think the nearest the society could get to something substantial in reality is tracking a link from jwn to jw.org and then the user logs into jw.org. Even that does not prove anything. How can you prove who the person was that was using the computer? If the source page is private then you have no idea what the person was looking at. Given the Ip address is likely to be in an ISP pool then you have to ensure the action was in the same session. There are privicy issues as well. I don't think the society could make something stick even in their kangaroo court world. At best, a repeated pattern of hitting jw.org from a link on jwn (or other site) and then logging in to a known account would only raise a flag which could probably never be used.
I think letting too much info out, poor browsing security, self-incrimination, mistakes, dobbing in by others and the like are far more likely to lead to a JC than any IP subterfuge. On top of that I think it's even more likely that the directly observable behaviour of someone fading or rebelling still gives the elders far more clues than anything else.