Don't really understand this need to reward. Seems the 'reward' is getting a place at the preferred school. My DS is encouraged to work hard on all projects and we certainly don't buy concert tickets etc every time he gets a good grade or tries his best at something. He knows we are proud whatever the outcome and there is less pressure in general if 'rewards' aren't expected.
My DS is encouraged to do well in everything also and he is not expecting a reward. However taking the 11+ is not the same as doing all his homework on time or to the best of his ability or going to judo every week even when he is tired. It is a big deal a real commitment he has made esp. In the months before the exam when he was doing practice papers instead of playing on the xbox like some of his friends who didn't take it. It has been a stressful time for all of us and I know some of his friends get taken to theme parks and football matches etc all the time for no reason. Unfortunately we are not in the position financially to be able to do that however on this occasion I feel he deserves something to mark the occasion. I do not see anything wrong with rewarding something worthwhile - if he does a particularly good job at school he is rewarded with merit marks. And yes if he gets into CRGS then that is reward enough however there may be only one or two marks difference between getting in and not getting in and if he doesn't get in does that mean he hasn't worked hard enough for a reward? Of course it doesn't!