My cousin (not Jewish) is coming in a couple weeks. Must remember to either a) take down Israeli flag or b) put up additional flag, this time American.
A couple years ago I was with her family and they saw someone waving a foreign flag and they flipped out and said that if they wanted to wave a foreign flag then they could go to that country and do so.

Upon further reflection, I think I'll buy an additional flag regardless of whether or not my cousin is coming. I think I kind of agree with my aunt/uncle/cousins that it's weird to be in a country, living in it, benefitting from it or whatever, and then flying a different flag. It's almost rude.