How 'bout a lasergrid fence? A 10 kW carbon dioxide laser should do the job nicely.

The two men were jailed for talking about the "Holohoax". No more truth to that than to tell that the moon is made of green cheese. Yet I haven't heard of anyone going to jail for spreading lies about the moon.

Get a mac, turn on parental control and the old geezers won't fudge up the computer, get an external harddrive, turn on Time Machine in Leopard for backups every hour. Now, should your folks manage to wreck the system, just reinstall from backup, it's a no bainer.