The only place XOR could be used is to replace the OR. As you say, replacing the AND NOT with an XOR would supress Alt + s.
Even replacing the OR with XOR is not obviously an improvement as it is not clear that we know what the correct behavior would be in the edge case where a keyboard event is emitted with both the control and command flags set.
Even replacing the OR with XOR is not obviously an improvement as it is not clear that we know what the correct behavior would be in the edge case where a keyboard event is emitted with both the control and command flags set.