easy and fast to use, but not quite as safe as I desired

I bought this product for installation on a GorillaPod tripod. The purpose was to be able to make better video and still images with the iPhone, even in unfavorable lighting conditions, including long exposures and time-lapse videos.
This bracket fulfills its purpose well. The mobile phone iPhone 6 may appear to fit well and is actually kept sufficiently safe. The screw thread for mounting on the tripod fits perfectly.
However, I'm gone for some time to use a holder with a stable screw for securing the mobile phones with the disadvantage that there will take the engagement of mobile phones much longer. I use the tripod again and again in situations where the whole structure is fixed but in a relatively large height above the ground, such as on bridge railings. There the springs based attachment mechanism seems to me sometimes just not enough to be sure, since the mobile phone if accidentally bumped could dissolve under unfavorable conditions quite it.
Who should have no fear of this kind due to the respective intended use, obtained with this product certainly something that fully serves its purpose, coupled with ease of use and affordable price.