We reported a couple of months back on LU's scandalous decision to hand Sophie Kyei-Donkoh, a Piccadilly Circus CSA, a 52-week warning for the "crime" of being abused by a member of the public (who was, in fact, a serial vexatious complainer).
Sophie's colleagues, through their local reps and RMT branch, organised to take a stand, and committed to balloting for industrial action if the warning remained.
Fortunately, management saw sense and the warning was rescinded on appeal.
It's a good reminder of what some basic trade union principles mean in practise: an injury to one is an injury to all, and unity is strength!