Made Me A Little Nervous

This couple, very inconspicuous in the background, made me a little nervous, because they were masking their faces.  I figured 3 possibilities: don't want to be recognized--but they hardly stand out.  Afraid police might use tear gas--but the crowd was very well-behaved.  Most ominous--did they want to incite violence and provoke a police response?  Fortunately, there was none of that.