DDOS? zero. There is no amplification, no redirection.
Someone can try to DOS you. But it'll be expensive. Your node will spawn a process for each transaction that hits your wallet, not for each output. You should strive to make the spawned process as light and short lived as possible, but for the most part, there isn't much danger.
Someone can try to DOS you. But it'll be expensive. Your node will spawn a process for each transaction that hits your wallet, not for each output. You should strive to make the spawned process as light and short lived as possible, but for the most part, there isn't much danger.
For reference, it actually runs the script twice, once when you first hear of it, once when it hits one confirmation (And thus hits the blockchain).