Quote from: o_e_l_e_o on September 29, 2021, 12:38:16 PM

Quote from: nc50lc on September 29, 2021, 04:13:00 AM

If it has an unconfirmed parent(s), any of the parent transaction shouldn't be marked as replaceable as well.

You shouldn't really accept zero confirmations for any transaction which has any unconfirmed parents regardless of their RBF status, since transaction malleability would allow a miner to invalidate the child transaction without invalidating/double-spending the parent transaction(s) (unless all the unconfirmed parents only spend bech32 segwit inputs).
-snip-

However there are Casinos that accept zero-confirmation deposits.
Since they are custodial, their primary protection against those who'll "cancel" their transaction is to lock the funds/winnings until the deposit has enough confirmations.
Rest are the rules and requirements like non-RBF transactions to qualify to that feature, I don't know if they are disqualifying txns with unconfirmed parent(s).