He suggested that in order for the stack to succeed, it must be exactly empty. This would make Script more composable and remove the need for special logic to handle top-level CHECKSIG versus mid-level CHECKSIGVERIFY. O'Connor acknowledged that this proposal was similar to what he had proposed in BIP114, but expressed uncertainty about whether it would do more harm than good, as people might lose money by copying an existing script template. O'Connor also brought up another related topic for discussion: pop the stack after OP_CLTV and OP_CSV. The same pros and cons apply.