There's nothing wrong with wanting to marshal pax off the movement area quickly for exactly the reasons YPJT mentions, but I get very sick of hearing about this sort of thing being blamed on 'security'.
It's not a security issue and if it is you'll be told very quickly on your way to the interview. If it's a pax control issue or a speedy boarding matter then just bloody say so. 'Stop dicking around and get on the aircraft' should suffice. Blaming it on 'security' is simply a cop out that weakens proper security issues in the eyes of the public.
When this sort of thing gets cited as security it all adds up to a complete public skepticism about the whole airport security thing, because it both looks and smells like crap. Just tell your pax to get a wriggle on and stop pretending to be something off the telly!