As an avid biker, I'm a big fan of safety. Other than helmets, lights are probably the biggest thing a biker can do to improve their safety on the road.
Unfortunately I live in a big mean city and like to keep my light in my bag when my bike is locked up. A problem I've frequently encountered with my light is that it will randomly turn on in my backpack far too easily which drains the battery. Very frustrating.
I was able to solve this problem quite elegantly with Sugru.
1x - planet Bike rear light
1x - packet of Sugru
Step 1: Make Flat Dot of Sugru
Make a simple dot of Sugru on a flat surface.
Step 2: Apply Sugru to Bike Light
Create a little pocket of space with your Sugru dot and place on bike light switch
Make sure there is empty space between your sugru dot and the bike light switch! This is what lets a finger push to turn on the light and not books in your bag.
Step 3: Let Sugru Set
Now that your Sugru is applied you need to set your light somewhere where it won't be disturbed. This will work much better if you maintain the little pocket of space around the light switch and don't fiddle with it.
Leave to set for 24 hours.
Step 4: Finished!
Assuming you followed the steps correctly you now have a bike light that is much harder to randomly turn on in a bag!