I agree, they should probably close off the tow-in / marshalling area,but I am reluctant to criticise them as I'm sure they do the utmost with what they've got and rely on fair play and common sense from Joe Public to behave sensibly and respectfully (naive I know) , sadly the nutters will be the first to scream if anything happens to them as a result of their own stupidity.
Possibly more alarming was the amount of people walking around in fully-badged flying suits who had no involvement with any of the aircraft present or probably any aircraft anywhere? !? There should be a law against it !
