Enjoy the attention, Smile and say " Yes...can I help you?" pull a face, prepare a little notice with words printed on it ....like Staring is rude or yes it's a wheelchair
Just look back and stare until they stop looking at you. If they get aggressive, just say something back, if they want to fight, just let them get close and within an arm length just put 2 fingers against their throat, they'll walk right into it and get knocked back a little, and then they'll scare out probably.
I am just trying not to deal with them when I am on crutches.