MeAgainAgain
The content controls provided by the ISP, at were part of a campaign by various newspapers, politicians and sites like MN that brought in the requirement that in order to have unrestricted internet access you had to opt out of the "family" protection. it included porn searches/websites and illegal torrenting/streaming services.
It lasted about five minutes until the first work around but is still in place, it is this system that was accidentally "turned off" by your ISP.
You are saying they shouldn't trust them anyway?
No you shouldn't trust them because your children know about proxies, vpns, streaming services and various other apps. And of course human error when mistakes are made.
You have available to you
parental web access programs
blocks that are available through windows, IE, chrome and other browsers.
You can set up blocks on google search (its actually safe search as standard and you have to turn it off)
blocks through your router
blocks through your ISP/phone provider.
You can even get your phone provider to turn off the internet to your child's phone. (or not buy them a data package) + parental blocks on the phones.
Yet children still find away to access porn on their various tablets, pc, laptops, phones.