I made a two tier cake and on the bottom tier I did rose swirls.  Well, I had frosted it with Pastry Pride and let it sit then covered it in buttercream rose swirls.  After about 20 minutes while I was transporting it, the flowers started to slide off on both sides! I don't know if it was the pastry pride, the heavy buttercream rose swirls, or that I just didn't push in hard enough to the side of the cake while making the rose swirls! I had to wipe off half of the cake and start over :( It was not fun

AI'm going to have to say it was the pastry pride. It's really the only thing I can think of. It's really soft. Perhaps it started to soften in transport and the roses couldn't stick?

I'm sure it was the Pastry Pride.  The product isn't sturdy enough to support the weight of heavy piped buttercream rose swirls.  PP is light and airy and the weight of the BC likely just deflated it and they fell off.

Probably better to have done the swirls with PP or done it all in BC.