They already do, however this is usually given the trappings of SOP and/or official investigation.
I think that what we should be on the lookout for is a drop in info from any midsized cities, an information-blackout could indicate things happening.
The other way for a big operation to go down is as response to 'terrorism' which may or may not be a false-flag op.
Arming all the administrative agencies,but willing to destroy all the surplus 223 ammo...You tell me !