Is this GCSE or A level? I think they'd probably tell you there and then..but then again its been years since I was at school..but I remember being told that if were caught cheating, we would be instantly disqualified so i assume its pretty instant if they decide to do it..passing someone a pen is a pretty innocent mistake to make, the invidulators are human as well and i'd hope they wouldn't make you fail a subject just because you were being kind hearted!