Finding "Half-Signed" Transactions

[AsymmetricInformation]

Hello, I'm curious about something and could not find the answer.

Situation: "A" signs a 2 of 2 multisig transaction, sending to "B". It still needs to be also signed by a third person "C" to actually go through, but C doesn't know who A and B are, and is never told about this transaction.

1] Can C use the blockchain to find a broadcasted half-signed (signed only by A) transaction? Ie is a "find all mutisig transactions that pubkey X still need to sign with its private key" operation possible?

2] Can A write a transaction that has two outputs, one multisig 2 of (A, C) to (B), and another single-sig to C (containing a tiny amount) to aid in this purpose? C sees that he has received funds, goes to the originating address, and signs the yet-to-be fully signed multisig transactions.

Is it even possible to broadcast "half-signed transactions"?

Thank you!

[1715189938]

1715189938

[grau]

"half-signed" transactions will not be included into the chain and will not even be sent or relayed by the standard client.
They might become useful with some protocol extension for which numerous suggestions float around here.

[AsymmetricInformation]

Darn. Ok thanks for the reply.