Ellis Vener , Mar 23, 2011; 02:36 p.m.
While it is always better to get a model release but if you are in public and the usage is strictly editorial or art in nature (and the question is: how will you control or police that?) a model release is not necessary -- at least in the USA.
this is not a legal opinion (no.1 I am not a lawyer, no.2: I am not your lawyer.) so if you really want to know a real legal opinion, ask an attorney who is versed i nthis area of the law.