A view from across the pond,
Apart from the idyllic (trad) songs, it seems that most modern songs are likely to contain some political comment.
If I was to go to a gig like yours SOL, I wouldn't be at all surprised to hear something political.
I'd be astonished, however, if I heard a song in praise of George Bush or Margaret Thatcher!!

Folk song has always been a vehicle for anti-establishment views.
Sometimes it's the only way for little people to have a voice.
I say, let them sue.

You can always quote that line from your National Anthem in your defence.
"The Home of the Brave, and the Land of the Free"!!!