Apparently there are now 15'000 heavily armed men guarding the inauguration ceremony.
Given that almost 50% of Americans voted for Trump, we can roughly guess:
Let's assume 30% of those guards are Trumpists, so 4500 Minitrumps.
Let's assume that only 0.5% of those are Trumpnutjobs.
That makes roughly 20 heavily armed nutjobs at the ceremony.
Now if I were the guy organising the event,I wouldn't worry too much about the nutjobs trying to come to DC for the event, I'd rather worry about the nutjobs already here...