As a kicker to the fact that it is one account per isp per household... You also have to use your own computer for just your offers solely. So if you use your laptop at your house then go to a friends house and they use your laptop at their house with their info will be noted. FusionCash may eventually shut both accounts down or it could just be an idle threat posted in their TOS. Either way, I wouldn't risk it with my account if it were me.
These rules are pretty easy to abide by and I can understand why FusionCash implements them. Their rules are pretty generic meaning that many other GPT websites have the same rules. Make sure that you always read the fine details when singing up for something.
(Especially with offers...)