Safe to proceed

This is RAF (Royal Air Force) Holbeach, an airbase with no hangars or runways, just a few targets for practising fighter pilots who fly in from various regular-type air bases such as Mildenhall, Lakenheath and Marham. 

A few warning notices are around the place including one warning members of the public not to pick up items which might turn out to be unexploded ordnance.

Should I hand back that red bottle-shaped heavy object that keeps rolling off the mantle-piece at home?