I want to write code that accepts a transaction, and afterwards "pays back" some amount to the origin of the transaction.
Assume users will be using the standard client. Will transactions have a single input, or must I handle the situation where a transaction have multiple inputs?
Can I just choose one of these inputs and pay back to that input? I want to avoid having to request users from entering a payout Bitcoin address - it's so much neater to just pay back to the same address they used.