Hello Chris,
Thank you for responding. Understanding the teaching dynamics is very important here. There is not a reason to include this plugin in the core if it does not meet actual use cases properly. We need to identify those as we are best able.
I have used some similar plugins to allow late access to the quiz, but with a reduced grade. You may be more interested in something like that. Unfortunately I have not used them with STACK before and that may have complications since STACK has some additional question behaviour plugins.
I have not yet submitted those plugins to the plugin database because I think more discussion and testing needs to be done. However, they worked well in practice my context. What behaviour precisely do you wish students to experience after the close date?
Daniel