Actually the more ventng the more to worry about. The venting we see at yellowstone is not the volcano venting, it is groundwater being heated by the magma chamber. the more venting the closer the magma chamber is to the ground water and the earth surface. If the magma chamber gets winin a few miles of the surface ...... BOOM!
Volumes, in cubic miles, of major eruptions (the last three are Yellowstone):
Mount St Helens, 1980 -- 0.24 c.m.
Pinatubo, 1991 -- 2.4 c.m.
Krakatoa, 1883 -- 4.3 c.m.
Mount Mazama, ~ 7600 ya -- 18 c.m.
Tambora, 1815 -- 36 c.m.
Island Park Caldera (West of Yellowstone), 1.3 mya -- 67 c.m.
Yellowstone, 630,000 ya -- 240 c.m.
Yellowstone, 2 million years ago -- 600 cubic miles!
Other "Yellowstone" eruptions may have been larger, but are impossible to measure. The main evidence they've left behind is in the form of the Snake River Plain. The mountains that once stood there were destoyed by successive eruptions as the Yellowstone "hot spot" moved beneath them.
There's a big difference between a local "BOOM" caused by water/magma interaction - which has happened thousands of times at Yellowstone - and wouldn't affect anyone outside the park.
There's no indication of any sort of imminent caldera blast at Yellowstone. It likely would take several thousand years minimum if there was going to be one for the chamber to become fully primed, based on what we've been able to divine about the magma in the chamber.
Overall there's such immense amounts of mythology and nonsense in this thread I don't know quite where to begin.