
I've never heard of one like the PP described. In my experience any showers or milestone celebrations for office people are just cake in the boardroom. Somebody makes it or it comes out of petty cash. I've not heard of people going out for lunch. I guess then unless the company had a policy to pay for it, everybody would go dutch or split it and chip in for the person being feted.
I can appreciate though that she mentioned it was the 90's - things were different then. My current company, where I've worked for 15 years has never had a "go out for lunch" culture. Honestly, nobody does it, at least not with coworkers. Most of us eat at our desks and work through, a few go for a walk or to a nearby gym. It's not even a thing anymore for vendors to invite us out and that's even in pre-Covid times.