It will introduce noise onto the network and create a signal leak.
If its still connected put one of these F couplers on it
http://www.worldvu.net/au/products_images/F_Connector_Joint.jpg
Which can be purchased here,
http://www.ebay.co.uk/sch/i.html?_nkw=F+coupler&_sacat=293&_odkw=F+connector &_osacat=293
Then cap it off with one of these F terminators
http://www.ebay.co.uk/sch/Sound-Vision-/293/i.html?_nkw=F+terminator
Can try reporting to vm but the chances of them actually doing something themselves might
Not be too great as their general attitude is your services are working, there is no fault so it doesn't justify a service tech visit.. It's more networks who are concerned about this kind of thing but I understand that networks can only be called to visit by a tech, not the support staff.
Make sure everything is tight just a little more than hand tight using a spanner when you carry out the termination then everything will be good
