0 conf issues
It might be possible for a bad actor to submit a transaction to the network that never has a chance of being mined. Currently, a transaction that has too low of a ringsize is still relayed through the network, so it will look like a valid transaction waiting in the txpool to get mined into a block. However, it will never get mined into a block.

Also, kasisto should have a way of verifying that a transaction has been relayed to some other nodes - a quorum of random nodes. Just because a transaction is in the kasisto's daemon's txpool doesn't mean it will relay - I'm imagining a scenario where the customer uses the kasisto's daemon as a remote node to push a transaction.  A transaction with too low of a fee will just get stuck on the kasisto's daemon, so it looks like a 0 conf, but it will never get mined. 

