there's always at least a good 10 of them at the local subway station doing random bag checks every other day.
Random bag checks? Are they allowed to do that? With no warrant they can just search peoples bags?
Yes they are allowed to do that. It became even more commonplace after the London subway bombings. Coincidentally, I have only been stopped once to be checked in my life. I dont exactly fit the profile of a an individual who might bomb the subway.