[treis]

From your cite:

>Where a piece of information (such as an IP address) does not directly identify a person, that piece of information will nevertheless be personal data in the hands of any party that can lawfully obtain sufficient additional data to link the information to a person's real world identity

In a world of data brokers that makes IP addresses PII. The only way it's not is if you verify that there is no way you can lawfully obtain additional data to link the IP to a person. I don't see how you can practically do that.

[AnthonyUK]

In UK it is not even a requirement for an ISP to keep those records but that is not the topic to address, so who is able to legally obtain that data and is it something that you are reasonably likely to do?

You can see why people err on the side of caution.

[treis]

>who is able to legally obtain that data and is it something that you are reasonably likely to do?

Any other 3rd party that has obtained their IP address and can legally share it with you. That's the problem. How do you ensure that something doesn't exist? Practically it's impossible.