I think that a 20 second hug suggests that the trust is already in play.
If my bank manager were a woman I would likely try that. Lol
Let's try it!
And I feel the oxytocin before I hug... sounds like a case of classical conditioning to me!
If it lasts 20 seconds or more, I'd hesitate to call it a simple hug though....<3 the Oxytocin.