Only travellers are allowed on to the platform at a railway station, preventing non-travellers from seeing off family and friends.
A few station operators have phased out the use of discretionary platform-only tickets for commercial and operational reasons. These reasons include ticket barriers and the need to combat fare dodgers in some locations. Most railway stations do still accommodate non-travellers on their platforms to meet and greet loved ones but some may take the reasonable step of suspending this at really busy times if platforms are crowded. In this latter situation it may be that “health and safety” is used as shorthand to explain the reason but this is not a valid excuse at non peak times.