Unfortunately turning it off would then prevent others from using you for boosters and training or from trying formations against yours without your Managerial Genius interfering. So what you see as a positive impacts negatively on others.

I regularly get farmed for boosters or 'tested' and I don't mind one bit....in fact it gives me another opportunity to see performances under unfavourable conditions.

If this was implemented then I'd like it a condition that the team refusing friendlies couldn't play them either for a time period - I don't want to be thrashed then denied the right for revenge