Someone else said you pay your money and you take your chances - It's his clutch and driveline and if he wants to do burnouts - let him do so and have a lot of fun. Its not fun to me, but neither are any of the "ball" sports.
However, what you FEEL about the subject, with relation to how tortuous a burnout is on a clutch is not helpful. Feelings are not helpful with relation to parts pushed past their manufacturer's engineering standards. A burnout is certainly that. Even with a new non-defective part it is dangerous. You can be seriously hurt by an exploding clutch and it happens frequently enough that most race sanctioning bodies still require special equipment.
That doesn't mean I'm dumping on anyone - but feelings are totally inappropriate when you are talking about high speed equipment.