What the initial poster meant to complain about was:
A PC using a "readied action" to cast a "silence spell" in the vicinity of an enemy spellcaster when the enemy spellcaster starts to cast a spell.  Or even better, when the enemy spellcaster "speaks with intent to produce a magical effect" which should cover activation of wands, other standard items, as well as spellcasting.  (although more than a little rules lawyerish).
A spell interrupt action, if you will, but instead of arrows you use another spell.  Perfectly valid by the rules.
This is how a 1st level Bard with a wand of silence stops the 15th level wizard from casting any spells other than silenced ones -- which typically are few and far between.
I mean, a silenced fireball?  Have you really seen one?  And if you had, is it right for a 2nd level Bard/Cleric spell to make a Wizard 15/20 worry so much (you MUST have the silent spell feat or you MUST have a silence metamagic rod).
Either way, the low-level silence caster is happy.  He's caused his enemy quite a headache, whatever the result.
The only easy way out is to have a globe of invulnerbility up before the first "readied" silence goes off.  That means, well, instead of blasting the party the enemy wizard put up a globe of Invulnerbility.  Party still with the net gain.
A dedicated "anti-caster silence slinger" bard cohort is vasty under-rated as a companion.  The party will love him/her/it!