Make your point of view absolutely known in your introduction, or you may be kicking yourself for years. Also, remember that there are probably quite a few in the audience who support your aims but are afraid to speak up.

Chances are the worst that'll happen is some will ignore you. Make sure the cheque doesn't bounce!

I've played a few times for groups who've liked certain songs on various of my albums but completely missed the message of several others. It's more interesting than preaching to the converted.

Good luck, you'll be fine.

Rick