I hope this is a situation where I'm going to take a deep breath and not make any rash decisions. Dwayne is 12-years old. He's not an adult, and I shouldn't expect him to reason like one. And honestly, I've dealt with enough 'adult' employees who have selective memory that this kind of thing shouldn't surprise me. For that matter, I remember Ralph yelling at me (and punishing me for) not remembering to take the garbage out, before leaving for school, twice a week, though I could 'remember all about those damned comics.'
In a lot of ways, this is my own fault. Dwayne's right that it's not fair he has to do the dishes by hand, when he didn't use the last lozenge, and it's not fair for me to blame him, when there were three other people who should have noticed we were almost out (including me).
(While the scenario doesn't say anything, I'm wondering how far the nearest store is, and how old big sister is, that I couldn't have just sent someone to buy more of the darned things. For that matter, couldn't I even have just let Dwayne rinse and load, and we could have washed tomorrow).
As it is, I'm moving my work stuff into the kitchen, so I can try to finish it up while supervising all 3 kids cleaning the mess - with the instruction that they all now know why not to do that, as well as having a good reminder to report when they're running out of the detergent.
No spanking for this, but any attitude from this point will be treated with little tolerance.