scratch

I was wondering if anyone uses a lens protector either something like the tempered glass you stick on phones to protect or something like those filters you stick on (except normal)?? Just been out a few times and often get bits on the lens and end up wiping with a glasses cloth - I am just...

Sorry if this a dumb question.. I just got this Phantom 3 Pro 2 days ago at Best Buy and last night i was looking under the motor mounts and I noticed a line coming from the bottom right screw to the light. I am not sure if its one of those stress cracks or just a scratch i somehow accidentally...