There does seem to be a witness.
If he corroborated a strike, now what?
In the hypothetical... the customer calls the police, wants to file charges and the other customer corroborates the “complainant’s” story.
Usually, a report is then taken and filed.
The complainant would have to see a prosecutor and a warrant/summons could be filed against the clerk.
At that point, there would be an initial appearance, the clerk could appear with private counsel or be appointed a public defender.
He would enter a plea.
In all likelihood a pre-trial would then be scheduled and the complainant, defendant, both prosecutor and defense counsel would meet to see if the case could be resolved without going to trial (plead to a lesser offense like a disorderly conduct).
If there are medical bills, they could be part of the plea agreement.
If there is no resolution at pre-trial, then a court date would be filed, subpoena’s issued to all parties (including the witness) and the defendant would have the option of either a court trial (judge) or a jury trial.
It would be highly unlikely the clerk would be arrested on the spot unless he started getting stupid with the responding crew or had outstanding warrants. Again, I don’t know Georgia law, but since this is probably a misdemeanor and the responding crew did not witness the assault, it would probably play out as I stated.