Whilst I agree it's probably unlikely, there is always the possibility. I gave up being a safety rep a few years back but will don the hat again for this one.
Lets say there are two people standing next to the wall having a chat. One of them raises a hand to express a point, or point at something to the other person. As he/she raises their arm the back of their hand scrapes across the protruding screw head and they suffer either a cut or a deep scratch. That in itself is grounds for a claim. Lets take it a little further. The cut/scratch is not immediately reported or properly treated so develops an infection, (doesn't have to be a serious infection but an infection is an infection). This could give grounds for a bigger claim if they could prove where/when it occurred. Such proof could actually be as simple as posting on a social media site a picture of their scratch/cut on the day it happened to let their friends know what happened to them when they were in Wetherspoons for lunch.
Sounds a bit far fetched I know, but after sitting on safety panels over a number of years nothing surprises me when people report an incident. Once came across a guy who had trod on a nail in the service yard. He put a claim in and the company refuted the claim as he was responsible for ensuring the yard was kept clean of debris at all times. Went before a tribunal and the tribunal rejected his claim because, a/ it happened mid morning after he claimed to have already swept the yard. b/ the nail was sticking out of a piece of wood he stood on, which should have been removed when he claimed to have cleaned the yard earlier, c/ he admitted that after he had cleaned the yard earlier no one else had been out there and there had been no deliveries. He was there held responsible for not ensuring the yard was clean and safe.
By the way, I was not an active member in this case, merely an observer that all rules were being followed.
