Normally I would agree with you, but recently it was added so that you could modify the data of the spawner and spawn not just sand, but any block as a semi-feature. Why add a feature if you're just going to make it obsolete later?
The point is, it works properly in 1.4.5, however it does not in 12w49a.
Can you read my whole post, please?
Upon further testing it seems as though it's not the fault of the snapshot, I don't really know what caused it. In the previous version of the game it wouldn't crash, though, which is strange...
So I guess this is resolved as an issue of my incompetence although I don't know how it happened in the first place.
You're right! How bizarre – it changed from a red wool spawner to an invalid one. I'm not sure if this is due to a mod I was using at the time or not, I'll experiment some more.
Hmm possibly... I switched it to peaceful after I died as I had no other sword to kill off the pigmen - they could have equipped the armour and then despawned... oh well - I'll get back on the grind then ☺