I use that form when traveling abroad. Just remember to have it signed BEFORE leaving. Every time I go to get it signed, the CBP officer looks at me like I’m out of my mind. However, when returning from Mexico, I was asked if I wanted to declare anything and I did not. They open all of the camera gear and told me I might be in trouble. I whipped out the form, they looked at each other kinda funny and let me pass.