Seen or had happen?

I'm 18 months out of school and I've received half a dozen jobs offers through informal connections made randomly by reaching out to people that looked interesting. Send a message that shows that
1. You don't want to sell them anything
2. You are curious about them/their job/industry
And odds are in your favor that they will respond. In fact, I spoke at a conference a few months ago on this very topic, and someone asked "what percent of people respond?"

100% if you know how to ask

That has been true for me up until I reached out to Bernard Marr. If you don't know who he is, you can find him by looking at the top posts on linkedin

To answer your question, the craziest thing I've seen is the power and opportunity created by a one-off InMail with the subject line "coffee or beer".