I mailed all of mine. It was the reason that I selected the bracelet & earrings (Etsy) for all of my girls. I got good quality. But It was cheaper up mail them then larger stuff. Plus they came in their own boxes.
I made time to visit each of my bridesmaids. I live in Houston. 2 are in Houston, 2 are in Chicago and 1 is in Las Vegas. But I don't see them as much as I would like so I used that as an opportunity to spend time with them and give them each their proposal box. I also think that mailing the boxes are just as special. It is an honor to receive one, especially if it is creative and/or personal. I received my bridesmaid proposal for my friend's wedding and LOVED it!!!
One of my college friends lives in Tennessee and couldn't make it for the engagement party where I asked all the girls. I mailed her the box and told her not to open it until the day of. We all face timed and opened the boxes together and it was just like she was there with us!