Hi MysteryMan
Whilst the Guest Wi-Fi does block anything illegal, it would not necessarily block what is deemed unsuitable. Unfortunately there is no way of setting it up those controls on a Business Hub. You should be able to do this with certain 3rd party routers however, but not on the Business routers. I do apologise about that. It may be worth giving our technical team a call on 0800 800 154 however to go through the Guest Wi-Fi with you, as it is a free service on the SmartHub, and may be suitable for you. It is quite a new service so chances are you will see controls brought into it in the future, as the demand is there I completely agree.
Regards
Ryan