Can I say I told you so?

I remember when Annie was young and I had her to a well visit to the pediatrician, and he had this big speech about not saying "No" to you kids. Yep, that's right, he told me NOT to say no to my kids. Instead your distract, or re-direct, or any of those time-consuming options. But me, when my kid is running out in the street...I'm the mom who is yelling frantically, "No, you can't run in the street", or when my child is pulling up the flowers that I just planted, you can bet you will hear me yelling "No, you can't pick my flowers!". It might be hard to believe, but when I say yelling, I mean I probably am yelling too. So that would mean I have 2 strikes against me now.
So, my question is this, what about "I told you...". For instance last week we had just come home from Sam's Club, Jon was on his cell phone, and I stepped outside the garage to spray something off. I asked Josh and Jake to take the gallons of milk that were in the back of the car, and put them up by the fridge so I could put them away. No sooner did I start cleaning when Jake came running out of the garage...
"Mom, the milk is dripping"
"It'll be okay, put it by the fridge", I said unconcerned
"No Mom, Josh made a milk fountain!!"
Afterwhich he turned and ran back into the garage. I turned and hurried after him, imagining the worst, and to my surprise was greeted by a river of flowing miilk that was quickly making a "Milk Pond".
Now, here's the point where it enters my mind that this situation doesn't call for a "No!", I'm thinking it calls for an "I told you...not to slam the milk onto the floor!" I guess I'm just starting to wonder what emotional scarring I may be leaving on my children to be saying such things to them!! Luckily I didn't lose my cool, and no, I didn't even yell, I just calmly said...exactly what I was thinking. Josh doesn't seem to be scarred, but I think he learned his lesson about slamming milk down on the floor--and Jake probably did too. I am just thanking my very lucky stars that they didn't decide to do it in the house and only one gallon broke!!!