@DH, after sending a transaction using old coins existed and generated prior to the block 460,000 couldn't either parties(nodes) be programmed some how to cross reference the both chains to see if a transaction is being double-spent?
Yep, so you'll know, but you can't do anything about it.
and how can someone send your coins from other chain without your permission if they don't have the private key?
They don't need it. The only thing you need the private key for is to sign the transaction. You've already signed that transaction, so it's just as valid on the other chain.
Also miners could as well ignore all transactions and mine empty blocks for as long as it takes to sort things out correct?
Sure, but why would they?
Oh! Thank guys. I understand it now.