The concession doesn't cut quite as deep when you combine it with CHECKSEQUENCEVERIFY to remove the need for the third party signature after a period of time.
IF
2 <Your pubkey> <Green Addresser's pubkey> 2 CHECKMULTISIG
ELSE
"6h" CHECKSEQUENCEVERIFY DROP
<Your pubkey> CHECKSIG
ENDIF
Imagine there is a bitcoin mall of the future where you can spend with 0conf to your hearts content. You walk in and send the funds you want to spend for that day to a 2of2 CSV address created with one of the mall's public keys. As you buy your items you pay for it from your green addressed 'mall' wallet. The retailer lets you walk away immediately, 0confs, because they trust the mall not to double spend the transaction. When your day is done you can either ask the mall to send you back your change; or, if they don't, then you can wait for the CHECKSEQUENCEVERIFY time to pass and spend them all by yourself.