Never yet seen a prosecution for declaring a pan or a mayday in the UK.
I read an interesting article in one of the US magazines a little while ago about declaring emergencies and when to do so; not that I get my flying technique out of magazines but it made the point that if in an abnormal situation you end up busting a regulation or indeed as so often happens in the US find yourself having legal action taken against you after an accident/incident by a third party/passenger or their estate the fact that you had made ATC aware of your emergency situation will likely reduce your legal exposure.
As PPLs there is always a tendency to try and appear and sound as outwardly professional as possible, especially to ATC, and there is the fear of being 'judged' by the professionals on the frequencies and the controllers for appearing to ask for extra help. I sometimes wonder whether this tendency is less in the US because controllers are more used PPLs in busy airspace and know that occasionally they will make mistakes through the overload that comes from single pilot flying.
Who knows, perhaps had the BHX guy asked for a delaying vector, told the controller he needed a bit more time before being cleared for the approach to configure the G1000 properly (which can sometimes take a while!) or just made ATC aware that he was getting a bit overloaded the incident may not have happened...and if it still had, the CAA may have taken a different view on prosecution.