Well maybe if your a public figure, leader, or creating the next generation you shouldn't be doing stupid things to begin with. If I had kids I wouldn't want them at a school that has this principle, who knows what else he does.
I think the whole "privacy" thing has gone to far. If you did something stupid you can't just pretend it didn't happen. Own up to it, learn from it, move on. If you fill out his form it just goes to show that you really haven't learned anything and should be trusted anyway. I would hope that Google keeps track of these and lists them in a database somewhere, let's see who wants there past erased.
You would judge the school based on weather the principle took a leak in public or not? How would you like not to get the job you want for the rest of your life because you were rolling a ah heck and someone took a photo of you...made it a meme.
Personally i don't find pissing in public such a "capital offence", it's uncivilized but also natural. And why not blame it on the society because it doesn't standardize public restrooms? We have set social standards that are not backed up by infrastructure - it's development done bad.
As you put it, everyone does stupid tings at some point and stigmata are a way for lazy people to have their judgement of another ones character done for them.
Or better yet, as Gandhi put it: “Freedom is not worth having if it does not include the freedom to make mistakes.”, tough i think i've reinterpreted the message to match my argument a bit.