Industrial relations - how to be a dictator

It seems that the private sector is also occasionally troubled by petty-minded bureaucrats. The Times reports:

Royal Bank of Scotland has sparked a fierce row with unions by threatening 14,000 staff with disciplinary action unless they open and have their salary paid into a current account with the group.
An RBS spokeswoman refused to rule out the possibility that employees could ultimately face the sack.
The bank, home to Direct Line, Churchill and NatWest, has written to thousands of employees warning them they will be in breach of group policy unless they act.

Regardless of the merits (if such exist) of the policy, why does RBS draw attention to it? Do they want to be seen as vindictive, tyrannical, pettifogging employers? Do they not think about the damage such reports will do to their reputation? Self-defeating or what...