I have been compiling and presenting quizzes around my area for about 20 years and the surge of the mobile phone is a pain in the 'arris!! I always ask for phones to be off of tables and out of site prior to starting, there is also a printed warning on the answer sheet. Within the last couple of months I had to warn one team that I knew that they were cheating, having observed them and also told by other teams that underhand tactics were being used, I was very diplomatic about it and only warned them, but the amount of abuse that they threw at me was unbelievable, the women were effing and blinding and accusing every other team of doing the same, they haven't been back since! It is quite difficult to keep and eye on every team, sometimes I get up to 20 teams, around 100 people, scattered about the pub, I do my best and I think i'm 'cheat free' lol. Also, the quizmaster IS always right, even if he's wrong, there can be only one answer, the answer that I have! Mistakes are made, we are human, but I make sure I double check all of my answers, it seems to work in the couple of weekly quizzes I present, I just love doing it. :)