>>1
Proxy checks are not reliable.

It is never good idea to leave anything unattended for that long. You will not die if you check the board at least every other day.

From my experience, the best way to hinder posting of cp is to check board often and ban abusers promptly -- pedophiles roam on the internet in search of abandoned imageboards and probe them by posting cp. If you are away for too long, they call their kin to your site and you know what happens next.