Humans, in general, are a source of mixed feelings. The source much joy and happiness but in numbers our fellows can be the source of great danger. Even a happy, friendly crowd can cause harm.

http://www.slate.com/id/2209135/

No need to avoid crowds in general. The experience of being in a crowd at an inspiring event can be very gratifying and should not be missed. But while your enjoying yourself you can lower the odds of being involved in an accident by staying alert to the signs of potential danger and know when and how to extract yourself.

Get involved. Participate. It is your right, perhaps your duty, to be engaged in public life and politics. Just stay aware of the potential for danger and act accordingly.