I'm not going to list all the acts you could do with a perfect stranger that you just met but will wager a bet that it won't include one of the most intimate yet very public displays of affection: holding hands.
Folks that privately perform any array of actions in a forbidden or illicit relationship cannot hold hands in public. Think of any shunned pairing (bi-racial, gay, mixed religions) in an intolerant environment; holding hands could invite trouble.
From teenage to old age, it touches my heart to see couples hold hands. It is a proclamation. It's cute, endearing, innocent and yet deep.