If you are refering to the first (2) pictures it was obviously before the requirement for a 4 wire system on sub-panels. In this case it is clear their is a disconnect on the outside of the building and is in 3 wire…again probably complaint in the day it was done but not safe by todays standards.
While in MY opinion CODE goes hand in hand with safety since it all originates from the NFPA standards…
In your case here…you would not want to seperate the grounded conductors and equipment grounds because in this set up it is needed but would not fly in todays wiring methods for many reasons.
The reason their is a removal of the neutral to case bond at the sub-panel is to remove dangerous voltage from metal parts, ground faults SHALL BE removed by giving effective paths to equipment for an effective ground fault current path.
Putting potential neutral loads to grounded metal could result in electrified metal cases and so on for a lack of better explanation…been a long day so I am trying to be brief…
Load-side equipment to prevent fire, electric shock, elevated magnetic fields, or improper operation of sensitive equipment, equipment and circuit conductors shall be bonded in a manner that prevents objectionable neutral current from flowing on conductive material, electrical equipment, or on grounding and bonding paths. ( 250.6) This is accomplished by not having a neutral to case bond connection on the load side of the service equipment, except as permitted by 250.142(A)(1) through (3).
with that said…in my long winded way…it is not up to the current safety standards but again probably was at the time it was done so while I think you should call attention to it and most certainly is a potential safety hazzard…do it in a way it covers it but does not reflect something the client HAS to change but should think about changing…while you can suggest it…the NEC ( again in my opinion hand in hand with safety ) would say it can stay…but again not allowed in this manner today !