This seems normal? Groomsmen are supposed to be part of the groom's helpers/runners. Apparently the original purpose of the best man to act as the groom's backup in the event that one of the bride's loved ones tried to take her back from the groom (or the unwilling bride tried to run away). Official sword-fighter/protector type fellow.

I don't think anyone accepts being a groomsman at a wedding without expecting them to be tasked to do something to help out.