Online Quizzes and Exams

[the_geneticist]

Do your students with accommodations get extra time? What about low income students who may have to work during the only 24 hours your quiz or exam is available?

Yes, all students with the accommodation of extra time get the legally mandated extra time.  It's very easy to customize those settings in Blackboard.
I've told students that if they know they have a conflict or emergency to let me know ASAP.  No emails yet and their exam is tomorrow. 
As clean said, very few students will have an unavoidable conflict for the entire 24 hours.  I'm all for being flexible, but I'm not going to play the "what ifs" game to imagine a scenario where I am accidentally excluding someone.  If they have an issue, they need to contact me.