In Randori we teach the pupil to act on the fundamental principles of Judo, no matter how physically inferior his opponent may seem to him, and even if by sheer strength he can easily overcome him; because if he acts contrary to principle his opponent will never be convinced of defeat, no matter what brute strength he may have used.
Jigoro Kano

How often do we find that randori (free practice) quickly escalates into shiai (full out competition)? I find it extremely difficult to persuade students to practice the fundamental principles of Judo in randori. Instead, they want to compete only to "win". With less experienced judoka this situation leads to more use of muscle and less use of Judo technique.

One solution is to pair two students with different skill levels. This way there is obviously no need to compete and both can work on different things. The better student can work on the finer points and the beginner can work on fundamentals without worrying about getting beaten for his mistakes.

Do you agree that randori and shiai should be kept separate?

Students and instructors, what do you think facilitates better randori?