So, I have a basic 20 amp circuit running to my shed that I put in about 1 year ago. It runs a few floodlights, indoor lights, rope lighting, fans, audio rack for outdoor speakers, little intex pump, and various items. For the indoor/outdoor lighting and fans, I have a bank of basic light switches (total of 6 switches). Basic covers and boxes like these.
http://image.shutterstock.com/displa...k-95589970.jpg

I've been having a lot of neighborhood parties, maybe about 8 a year, and with parties, come the neighbors and the kids (about 15 of them). Well, beside for locking the shed itself (since I have games and a couch in there), I can't keep people and the kids from playing with the switches. Either messing up the outlet that the projector plugs into for movies, cycling the pool pump, or shutting off the lights as a joke.

I need some sort of locking cover or solution for the switches. Would it be okay to install a locking sub panel just so I can keep lock up the breakers and have them "not messed with"? Would I need a ground rod even for just a 20 amp circuit feeding it?