We have encountered a few cases where users have gone into Quiz administration>Edit quiz to modify a question and without realising have actually modified a Category (or higher) level question, rather than one confined to the quiz. This causes them to unknowingly change all instances of that question that might be used within in other quizzes.
I do understand that the question category displays at the top of the page, but I think an additional message to make the implications of modifying the question more evident would be very handy.
Example scenario: A question is created at a category level then added to a quiz. At a later time an eligible user modifies the question from the 'Edit quiz' screen in the course.
Proposed solution 1 - Simple:
A message displays at the top of the question edit page - "This is a <insert context> level question. Please note that changes made to the question here will reflect in any other quizzes containing this question"
The message will change based on which context the question was created at.
Proposed solution 2 - More detail:
As above but a more detailed message displays showing the number of other quizzes the question is present in.
"This is a <insert context> level question and is being used in <x> quizzes. Please be aware that modifying the question here will affect the question in these quizzes."
Proposed solution 3 - Even more detail:
As above but the number is also a clickable link to a page listing the names of the quizzes. Each of the quiz names are hyperlinked to that quiz's entry page.