Fred's pulling your chain. Walk up to them and aim your cursor at their head or the icon above it, then when you get the "talk to" prompt left-click.
Whilst I would love the mic feature to be real, solicitr is correct - you just need to head up to the passengers who have the ticket icon above their heads. It will not appear above every passenger, and should look like this: This will then prompt you to talk to them, and open up the ticket checking menu. Hope this helps, and good luck!
