Quote from: Andriian

Sorry, I didn't get the point here. type 3 is about this kind of locking script where Alice can spend anytime

Sry, I got CSV and nLocktime mixed up since Type3 can be achieved either way and the disadvantages are identical.

So it goes like this:

Quote from: Andriian on September 22, 2019, 09:36:55 PM

Code:

OP_IF
OP_CHECKSIG
OP_ELSE
OP_CSV DROP OP_CHECKSIG
OP_ENDIF

∙After the address was funded, the timer will start [1].
∙Alice can spend the fund anytime.
∙After , Bob can spend the fund in case something happens Alice.

[1] Alice will create a transaction that will send her bitcoins to that address but wont broadcast it, RAW tx will be sent to BOB.
This way, wont be active.
If Bob decided to broadcast the tx and it got included to a block, the address will be funded, thus will start the timer.

That will work even without automation.
A notification system should work to minimize the work for Alice to check every week/day if the address was funded.
But still doesn't totally solve the "fee" and "complexity" problem since Bob can broadcast the tx anytime
that will require Alice to make another Time Lock script (another transaction to transfer the funds) in order not to expose the redeem script and public keys for privacy (or future security) reasons.

This partially breaks the "trustless" system.