I have an upcoming wedding cake that is to be iced with Swiss Meringue butter cream. Can I pipe royal icing accents on it? Will the royal hold up? Thanks

Piping direct onto SMBC prevents your royal from firming up, and can make it actually run. Sorry, you'll need to switch to plan B!

I have had a different experience - I pipe royal onto SMBC all the time with no issues. So we are basically no help at all. lol

I'd say it probably has a lot to do with your environment and royal recipe. I am in Alaska so it's pretty dry and my royal is just whites and powdered sugar to consistency.