I've got to get one! I have 2 tricks. First, I cross my legs and at the first sign of reclining I jump, yelp and grab my knee, feigning injury, this usually frazzles the person enough not to try reclining again. Second, if that is not sucessful, when the person leans forward or gets up I quickly push the seat to "it's full, upright and locked position". Most of the time they don't realize that the seat it no longer reclined.