Of course, it is inappropriate to show up to a birthday party or shower without a gift, but not expected at the wedding if that guest attended the shower and gave a gift there. The guests at my shower didn't bring a gift to both and that was fine with me, I didn't expect it.
My mom's BF mother sent a second gift, but I didn't understand when she went one to the shower. My inlaws gave at the wedding, but they live out of town and didn't send agift to the shower. I actually would have preferred if my MIL had just forgotten all together, becuase she gave us some yard sale candle holders and a bride and groom beanie babies (some wedding gift)
I know some people that request no gift to a birthday party as they don't need/want anything and I have even seen a request for a charitable donation for birthday's and even weddings.
Why should the bride be hurt, she shouldn't expect somone to show up with a gift, especially if that person attended a shower for her. That is one greedy bride that expects people to bring gifts to the wedding, you aren't getting married to get gifts.
I would have been just fine without any gifts at all when I got married, I had already purchased what I felt like I needed and had some things passed down from my grandmother. I wanted my guests to be at my wedding to share in our love not supply my household.
If you will read about wedding customs, gifts weren't always a part of the ceremony at all and some gifts were food or spiritual offerings, or a dowry. We have gotten past the real meaning of weddings, similar to commercialism of holidays.
Suzanne