Our members are concerned about the shout box creating a security threat. Is this a valid concern?

I don't see it creating any more of an opportunity for hackers, spammers and trolls. Only in that the potential of attracting a few bad eggs along with a possible increase in web traffic.

Does anyone think that it would add a significant burden for the moderators?

I did a search for this but found nothing.
Thanks again for all of your help.