Spider goes from Predator to Prey

This Mud Dauber tricks the spider into thinking he is caught in the web.
He goes to the edge of the web and tickles it with slight vibrations.
When the spider goes to get his meal the Mud Duauber quickly grabs the spider and gives him a paralyzing
sting.
It still puzzles me as to how the Mud Dauber is able to navigate the web without getting caught.