I always do that when there are only a couple with me,i ask politely,but when there is a group of 20-30 people i don't think it would be particularly appropriate to walk along the entire line like someone with some position of power! I just think it is common courtesy,i always arrive on site if i am doing just fotting and look to see if anyone is videoing,if they are i shut my gob,its quite simple,surely. Shutter sounds i don't care about,they cannot be avoided but people have no reason to talk continually throughout the action! This is the main reason i prefer not to do too much linesiding at popular locations,but with the GC where there are only a couple of decent locations for vid/fot near the roads i have no option. The problem with doing both at the same time is i need to be in a good position to get both. There were a few of us doing vid however,at least 4 or 5,it is pure ignorance to keep gobbing continually. Like me going and standing with an orange jacket in the centre of the shot,now that wouldnt go down well,would it? It is the aparent attitude of larger groups which stops me and no doubt others asking them to be quiet,some,by no means all are likely to shrug it off and come up with a cocky,needless remark.