On the cake contest thread there's a GREAT post about tips for contests and one of the tips is:
"11. If you are putting sprays of wired flowers onto your cake, DO NOT stick them into the cake. This will be points off immediately. If the flowers must go into the cake, then use cake picks (or hide the wires very well). Let the judges know if you have used cake picks"
I've never used flowers before but have a ton of them for the dummy cake I'm making right now. I always thought that you were supposed to put the flowers in the cakes, but you need to be careful about not using exposed wire: use picks, chocolate, straws, etc. instead.
Are you not supposed to put gum paste flowers in cakes at all? Are they supposed to be adhered with RI instead?
The issue is not the flowers themselves, it's the wires.
I agree with the above post. Here's why: http://cakecentral.com/cake-decorating-ftopict-632290.html
You can stick them in, just dont use wires to do so. HTH!