The police have a database called pentip that records vehicle related so-called "Offences" and the responses to things such as S.172 notices for example. If you nominate a driver that cannot be traced then this is recorded; if you do it several times then the police think that they have some sort of right to investigate you. The funniest thing is when they try and take them to court and you put them to proof; they can have all the data that they like, but if they have no proof that the actual offence that they are charging you with has been committed by you then there is nothing that they can do about it other than try and scare you.
The simple way to defeat these intrusive databases is to put the police and the Crown to proof on every aspect. It costs them a fortune and they normally cannot do it.