Kibi didn't exist until 1998 (per your link), so anything you read that was written prior to that and for a few years after still has the kilo=1000/1024 ambiguity.

I know the 'kibibytes' thing but never encountered it in a real-world context (e.g. like "the C64 had 64 kibibytes of RAM").

I personally decided to just use them always for clarity and I saw few people around me catch on. Be the change you want to see, especially when it comes to the free minor stuff.