My 3 and 5 year olds will often avoid using a bathroom once they notice the automatic flushing toilets.  So here's a great trick passed along to me by an Occupational Therapist friend.  Carry a stack of post-it notes in your bag and simply cover the sensor to keep it from flushing.  Once your child is finished and has left the stall, just remove it so the toilet can flush !  This silly little trick has made life out in public so much easier.