First of all I take we are working on the basis that it is established beyond question that spanking offence has been committed and there is not question about if corporal punishment will be used only who, or whom, will end up with a sore bottom.
My first thought was that I would not have any second thoughts about whacking all of them. If they thought that when Reese said "I guess you'll just have to whup us all" they were calling my bluff I and I wouldn't do it they would find out they were wrong. No free rides.
Each would be receive the spanking as they would if they were on the only one responsible. I see no reason to dilute one spanking across some or all of them. It would probably modified for age and level of "should-know-better". It is, of course quite possible that all of them were equally guilty or at least equally culpable.
Jack described best what would happen next.
Jack wrote:"Well, I thought only one person had done it, but if you're all confessing, you can all get busted. Pants and shorts off, and nose to the wall, while I decide what to use on you all."
Although I would make it trousers off, nose to the wall and underpants down
. The reason for the difference will become apparent later on.
Jack wrote:If no one wants to confess....
This is the problem. In a situation like this, own up or everyone gets punished, there is no real incentive for the whoever did it to confess. Either way they will punished, possibly with a greater punishment if they do confess. That does rather counteract any altruism of wanting to save their associates from punishment. The school boy code or ideas of camaraderie would discourage anyone from revealing who really was guilty, it would be considered sneaking or worse and they would be ones in trouble afterwards. Sometimes that is a good thing but often it is not.
So how do you break through this wall of silence and group loyalty? What incentive is there for the guilty person to own up? Well, here is a suggestion though I have no idea whether it is likely to work or not. When the four of them are in position and I have chosen a suitable, if any, implement and am ready to begin the spanking then I would make an announcement along these lines:
"Right, now before I start whoever was really to blame may pull their underpants back up, even if think you deserve a bare-bottom whupping. This is your last chance."
That should give whoever is really did it an incentive and opportunity to make it known. (Though it could turn out to be a variant of Prisoner's Dilemma). Obviously those who pull up their underpants back up will receive the corporal punishment, and the possibility cannot be overlooked that they all might to it, if none of them do then they still all get spanked as originally intended.