How do you prevent tape from sticking to something?
The original Peter G
Put tape on your brother?
G. Whilikers
Why mess up *your* camera? The brat will just smudge the lens or something. Just make it Very Clear that it's in his best interests not to mess with it. Also, point out that it's very easy to assume he's doing something evil or perverted instead of just stupid. For fun: refer to your cameras in the plural, as in "please don't cover up my cameras, they're for the dogs."
spacemissing
Yes... but anything that will prevent the tape from sticking will also blur the image significantly. Try clearing the house of readily accessible tape. Maybe the lack of convenience will stop the problem. Or, maybe he will go to the trouble of buying more tape and win the battle.
AlCapone
Vaseline
Mountain!!
WD 40