Rather than take a chance on Sig's questionable quality I just choose to avoid them and purchase planes from Yellow Aircraft or other manufacturers that don't have those kind of problems. I one of the many that had a flutter problem with the Sig Cap - they never responded to my letter so I never purchased another Sig product. I have built quite a few ARFs and none needed the covering cut to check the wings. I never had a flutter or structural problem with any other ARF.

Just my experience - take it for what it's worth!