It'll mainly effect those channels that are the most dodgy, like The Great Big British Quiz and Quizcall
They regularly remind viewers on ITV Play to decide upon how many calls they will make and then stick to it, and use them wisely, so they are obviously working within moral guidelines
The ironic thing with this is they kind of go to both extremes, ranging from quizzes where the answers are blatantly obvious it's virtually random selection, too questions where the answer is virtually impossible (i.e. the "count the numbers" type games) it's basically random guessing.
Also though as I read this on BBCi I switched to Teletext to find out it's going to hit cinemas soon with a major chain signing up for "Big Screen Bingo" to air before films!