Not directly what you're talking about, but related: <a href="https://twitter.com/paulg/status/1122431284452761600?lang=en" rel="nofollow">https://twitter.com/paulg/status/1122431284452761600?lang=en</a>
It's valuable when you're at a startup event, so people who want to talk to you can find you. At YC Demo Day a good fraction are wearing their logos and they're much easier to find in the mingling sessions.