South Eastern avoids this by not announcing them at all. The train
will disappear from the monitor and run unannounced through a
different platform.

I've also known last minute changes happening repeatedly at Finsbury
Park.

I think the winner was at Stratford where the displays showed a train
due in a platform where the line was blocked by one of those red light
things.

I was astounded once to watch a train at Luton Airport Parkway announced as
approaching and then standing at Platform 1 with complete synchronicity.
The only problem? The train was actually approaching and then standing at
platform 3.

Off it went on it's merry way with the CIS still under the impression it
had been at platform 1.