I've heard these mentioned many times on the Honda-Hybrid group on Yahoo. Not sure if any of the people that have gotten them are on this site. I've heard of many people zip tying them such as you've done for security purposes. Lowes has an awesome bolt section too.
I remove my skirts about every 8 washes to thoroughly clean up in the wheel wells (I regularly drive on dirt roads though.
I did the same thing as you the first time I removed them except I found my screw later on. (in the driveway)