Anything that relies on configuration on the laptops will of course be subverted by any teenagers who are sufficiently not-lazy that they can be bothered to do it.
GTW, not if they can't log on as an administrator, and can't boot from USB / DVD as I mentioned.
Above all, make sure their accounts are User-level only and set a BIOS access password on the laptops (and if necessary a power-on password), so that if you want to block booting from Optical / USB drives it won't be (easily) bypassed.
SD