>> "Hi, I'm one of the 100K alumni who went to the same school as you did, can we do coffee?" is

I have absolutely gotten similar requests from students through my Alumni organization and have accepted them in the past. I don't see a problem here.

Here is a direct quote from a request that I have accepted in the past(redacted a little): "Hi <name>, I am a MS in CS student at <university> graduating in spring '25 and I saw your profile on <university>'s alumni page. I'm pursuing a career in software engineering and I'm wondering if we can connect and chat sometime about your career and the culture at <company>."

I was a bit flippant. Depends on the specificity of the request, how it's worded, and how big a request it is. (I'm far more likely to have a quick phone chat or answer a specific question by email than I am to drive to meet someone for coffee.) It's also a pet peeve when I spend the time to answer some questions and... crickets.