What? No you don't. You start with a Uw (or Uw') and insert 3 edges so that when you undo that move to fix the centres, you'll pair up 3 edges. Then you can either freely 2-pair the remaining edges or use a fixed buffer.
A. The silicone you used was petroleum based and it made your cube sticky.
B. You applied to much and you cube got sticky.
C. You didn't break it in enough IMMEDIATELY after lubricating it.
I do highly recommend checking the ingredients in your silicone can and making sure that it isn't petroleum based as this is the most likely reason why your cube is sticky.
Why do you get that idea? I don't see why it wouldn't be allowed. Just because a scramble give advantage to a few methods, doesn't mean it shouldn't be allowed.