Common sense says that the instructor is not going to send the student on a first solo unless he/she is fit for the task.
I know there is always liability to consider but I am getting a bit fed up with all this PC stuff. Our hands our tied teaching EFATO due to Rule 5 etc but they have to pass Air Law before solo!!
So we cannot teach him how to save his life if the engine quits after take off but it's ok to fill his head with all the air law guff.
I say that as qualified instructors WE are the people who know best as to whether the individual student is fit for the task on that day. Ask any instructor what it feels like when your fledgling pilot is doing a first solo!!