If your cake is completely buttercream, I do recommend you refrigerate your cake if the occasion is going to be outside and it is fairly warm and/or it’s warm inside your house.
Does my cake have dowels in it?
Every cake that has multiple layers will have wooden and/or plastic dowels in each layer for support. Please DO NOT smash someone’s face in a cake. (Smash cakes for birthday parties NEVER have dowels)