5 seasons, normally two games a weekend. Can't say these "purist" views have ever been an issue in any of my games, which always seem to go very well, with the exception of maybe two or three in all 5 seasons.
I honestly don't see how you can give a decision without being sure? Not saying I'm always right, I'm sure there's hundreds of decisions I've given incorrectly in reality, but the decisions are always "there is a foul / handball / whatever there" not saying "I'm 90% sure there's a foul, so I'll give it on the basis of probability"