ST
So taking legal IA is breach of contact. A company withdraws pay from its employees and they know in advance the consequence of their action, yet this is not seen to be a punishment etc etc.
A company warns its employees in advance of the consequences of their action, the withdrawal of staff travel privileges, that are not in any event contractual, and up goes the cry of punishment etc etc..
Had the withdrawal come after the event, with no warning, then possibly a case could be made, but in advance no chance.
While I fully understand those taking IA feel aggrieved, the way to get ST back fully is to accept the offer and over time re-negotiate the return of seniority to it. Assuming of course seniority is still legal after the 2006 age discrimination act is fully implemented in Oct 2011.