I got a nice thank you note a few days after the reception. "...The symbols were perfect, the taste divine..."
So use things on your cake that mean something to you, and don't worry if it's traditional or not. If it has meaning for you, go for it!
Kara Buntin owns A Cake To Remember LLC, online cake supplies at www.acaketoremember.com and www.acaketoremember.etsy.com