phoneline connection on multiroom is to recieve reduced subscription on 2nd box and so sky know also where the boxes are.
It is also part of a std installation for 1 yr box must be connected to landline to rewcieve incoming and outgoing calls, regular software updates/downloads to boxes and use of interactive services.
however if you are having 1 box ONLY and have no phone connection you can arrange a no phone install for £25 one of payment but you get no interactive services.
sommit to do with broadcasting legalities as to why only viewing allowed in uk/roi