I've been on tons of training exercises in foreign countries, and you simply do not establish tough perimeter security around the entire training area on the bizarre chance that some nut with a death wish is going to start shooting. You generally don't have enough people to do that, and frankly, its a waste of manpower.
From this point on, they may do that. But the effect will be to lessen dramatically the quality and frequency of training because you'll have troops who should be getting trained guarding the training area instead. In fact, I can't think of any exercises I've been on overseas where it wouldn't take more troops to guard the entire training area than would be training in that area.
And even at that, the training area would undoubtedly be drastically reduced.