I recently had an absolutely excruciating experience after a startup on HN made an offer literally 0 days after meeting with me. We met for a sandwich and 2 hours later I had an offer. Three days go by and the hotshot young founder has now found a new muse, we have a falling out for an absolutely contrived reason, and I'm out on the street with no job in a new state with no health insurance and having to break the rental lease.
Thankfully the next weekend, once again I clicked on the "Ask HN: Who is hiring? " thread and landed a new job, but this company took 50 days and a ton of coding interviews.
Better safe than sorry.