Passenger conductors

Hi, once I travelled with Metrolink and I heard the conductor say in his welcome&announcement over the PA that passengers must travel with a valid ticket at all times and travelling without one, could result in being fined or in being removed from the train. Is this standard in any announcement on passengertrains?
In Europe, the rules are pretty much the same, but we don't say over the PA what happens if you don't have a ticket. Officially we assume all our passengers have a valid ticket ( wich is never the case, ofcourse...).
I'm thinking of announcing a similar thing in some commutertrains.

I don't know if this is the standard announcement, but some conductors like to say it over the PA, while the others don't.
Are you a passenger conductor in Europe?

Yup, based out of Antwerp ( near Brussels ), Belgium.

That Metrolink announcement might be a little different because Metrolink uses a proof-of-payment system, versus traditional lifting/punching tickets and seat checks that most of the eastern commuter railroads and Amtrak use.