I'm going to wait if I see him being actually inconvenienced by it the next time he appears.
Their IC reasoning behind teleporting away at the first sight of danger isn't really important. What is important is that it minimizes or outright removes the consequences for their actions and their victims' ability to retaliate.
And Alexandrian: the problem here is that it's really not good if everyone and everything needs to have a teleport blocker just because people abuse teleportation. More importantly, not everyone can have teleport blockers, especially if they don't have magic or high-tech.