Another way to undersentence criminals.

The ways found by the system, to ensure that all persistent offenders are woefully under-sentenced, are legion.
Here is another.
Take Humphrey Bloggs, for example. He has a shedload of offences for drunk and disorderly, actual bodily harm, resisting arrest, affray, domestic violence, possession of class 'A' drugs, driving whilst disqualified, serious motoring offences and one instance of grievous bodily harm for which he was jailed two years ago.
He has now been convicted of a number of break ins of greenhouses, garden sheds and garages - let us say eight - and is up for sentence.
Surely, he must be prison bound - mustn't he?

Not necessarily! His solicitor will argue that these are 'a kind of offence for which he has no previous convictions'.
The Legal Adviser [Court Clerk] will re-emphasise this point to the magistrates and will suggest that effectively, Mr Bloggs will be treated as a first offender as he has 'no previous offences of dishonesty'!

Over years, I saw countless situations as extreme as this made up example.

You really couldn't make it up!