I've never heard of them failing someone in 1131 for not attending enough. On the other hand, if you rock up with a problem later in the session, or if you are sick for the final, they are likely to look at whether you have been attending before they do something like give you a deferred.
I usually find tutorials pretty useful - as long as I have done some problems beforehand, ie it is better to do them beforehand, then maybe skip the tutorial if you can do everything, than skip the tutorial and then try to do it all at home.