Question:
My SIL invited us to join her for supper in a resturant tonight, as a good by party for her daughter, I know this will mean a lot to her and her daughter… is it appropiate to be done in the 9 days?
Answer:
If it can’t be pushed off until after the nine days, it may be done, however it is better not to wash, so it won’t be like a real meal.
Sources:
Kovetz Halachos ( R S. Kaminetzsky shlit”a) Bein Hamitzarim 10-7.