Point me to the place in the ToS where it says “a fence foundation should ONLY be placeable one foundation distance apart”. For that matter, point me to anywhere else where Funcom said that. The closest you will find is the post where they clarify that fence foundation stacking (i.e. building them excessively in-depth to make your build stronger) is considered an exploit.
Similarly, I can lag the hell out of your client by placing hundreds of torches in an extremely small space. That would be bannable under ToS, not because you placed two torches close together, but because you abused the ability to do that in order to affect performance, which is what the rule actually talk about: