Mweb advertise on top of Teasers

What a Brilliant advert, snapped it on my way home tonight:The Mweb part of the advert reads: "MWEB PARENTAL GUIDANCE".For those of you who haven't seen the Teasers ad campaign - where have you been? - the ad below the mweb one has a revealing picture of a woman on the side...Mweb seems to be capitalising on this by placing their advert for their online parental guidance service over the Teasers ad.Sheer brilliance. But I wonder if Teasers needed to give Mweb permission or how the situation works? Any have an answer?