My husband and I are attending a vow renewal soon. The couple had a date set and were in the middle of planning their wedding when he received orders to go to Afghanistan. They chose to be married before he deployed. He returned home safely, and they are now having a vow renewal. I couldn't find a registry, so I asked them, and they said not to get them a gift- that the day is so they can celebrate with friends and family. Since they told me not to bring a gift, would it be rude to give them one? I was thinking a nice card with either cash or a gift certificate.