I don't get the "regional" aspect. Okay, somewhat I do, but to me--a niece is a niece. (Note: I only have 3. Well, 4, but one lives in another country and I've never met her). Anyway, we gave $500 to the one whose wedding we attended, 800 miles away. We also gave $500 to the one who got married in a park on a Tuesday--we didn't even get invited to that ceremony (which is okay--we were 800 miles away!). If anything, the niece with the cheap-o wedding needed the money more, and kudos to her and her husband for having the wedding they could afford.
I might feel differently if I had more nieces, or less money.