Completely anecdotal, but I was told by a lot of people in NN that jumping in front of or distracting someone clicking a placard is not harassment. You can use your keyboard to spam a placard to ignore all other targetables near you; I think it isn't harassment because there is a way to still play the game despite people trying to stop you. That being said, stop clicking and use your keyboard. In self defense, I like to jump around a placard and you can tell when people are clicking.