Stadiums represent a key focus for terrorism, as on match or games days they represent not only a microcosm of spectators, but often have VIP's in attendance. It would be difficult to patrol such areas using conventional chemical detection tools, stadiums are always large and the activities have to be intense, and these activities could alarm the visitors. Under these circumstances, it is best that any chemical technology is operated in a covert manner; often from a permanent covert installation.