i think it's important because it means that people who may have very minor offences on their record now find it extremely difficult to travel to the USA. we hear cases like that of a 65 year old man been refused entry because he had committed a minor breach of the law with an air-gun when he was 14. There have been many similar such instances and, whilst one appreciates the importance of cross-border security, it seems clear that many basically honest, law-abidng people are finding it difficult, inconvenient and expensive to enter the US. Due to the nature of the visa-waiver programme, a UK citizen travelling to america who has been forced to apply for a visa, even if successful, is virtually waving a flag saying 'i'm a criminal – strip search me and hold me in immigration for nine hours!'. In the meantime, true criminals and terrorists merrily skip from country to country with false identities and forged papers.
until the end of 2006 it was possible to apply to have one's criminal record erased in the case of minor and long-ago offences. now these offences, although they may only appear on a CRB at police discretion, remain on the PNC until 100 years after the death of the subject.