Earlier today I was flying along, minding my own business and dodging the showers. I was outside controlled airspace but listening to a local unit just to see what was going on.
A couple of Exam call signs were on frequency, both pilots on IR tests, both pilots undoubtedly towards the end of an expensive, intensive course. The first pilot seemed on top of things and was soon passed to London, the second pilot sounded more nervous. The unit I was listening in to cleared the second pilot to 2,500ft - but shortly called him to ask his altitude as it was indicating 3,000.
The pilot replied that he was correcting to 2,500 - but I'm guessing that the level bust was going to spoil his test. I can imagine how badly he felt as he pushed the nose down, perhaps taking his feet from the rudders for long enough to kick himself. As if that wasn't bad enough, ATC then called the Exam call sign to remind him that the previous agency had only cleared him to 2,500 - so even if by some miracle the examiner had been asleep/missed the mistake the first time around he/she was left in no doubt. I suppose there's a chance that the pilot got a partial pass, but a mistake like that at the beginning of the flight can't have done a huge amount for his nerves.