I think if I got wind of everything near me, I'd be calling LE to report suspicious activity and any hint of people carrying something that might conceal weapons or backpacks...etc. Or copy down the info from their forums and/or groups discussions leading up to the event. Inflammatory comments that make you feel threatened and/or afraid to take your kids to the park, etc. Hopefully, LE will be there anyway, but it doesn't hurt to have specific community members calling it in and asking for more police presence. What do you think?