Common Law - is legal convention based on decided cases. The Freeman of the Land b***x is a bunch of people trying to opt out of the law of the land. The problem is they can sound very convincing and will happily encourage stupid people to do stupid things. Its fine for them as they aren't the one getting their fine doubled or worse. Most of the speeding loopholes have been closed.
Refusing to sign the NIP was probably the best one of the day as it meant there was no evidence to prosecute the driver - but thats been closed.
The "Hamilton" is still a good one as is the "Clarkson". The Hamilton relies on the RK accusing another driver of being the driver and the other driver denying it. The RK complies with S172 RTA request, but the accused not being the RK has a lower obligation to provide info. The Clarkson is a variation that relies on a lease or hire car, such that the probable keeper at the time is not the RK. of course you commit perverting the course of justice if you are are a liar and get found out.
You can dodge speed awareness by booking and delaying, forgetting to pay, changing date etc. and then after 5 months saying - no thanks - by which time the original offence is timed out - they are wise to this now though.
I'm surprised more people don't go for the no number plate option as the fines are low