I have been watching a series of videos of a criminal trial in the USA.
I have noticed that exhibits for the defence are labelled with four consecutive letters but often (if not always) these letters are repetitive, e.g. JJJJ and KKKK. I'm on day 5 and have only just realised this so I haven't gone back to watch all the previous videos again in order to check. I'm sure about JJJJ and KKKK.
Here's an example:
Defence lawyer: I'm going to show you what's been marked as defendant's exhibit KKKK.
Why would the labelling have repetition? For example, why might it not be KAAA? Or simply single letters, J, K, L, etc?
At whose discretion/direction are the numbers allocated? The judge's, the counsels? Is there a standard or does each trial 'invent' its own standard for this?