That's a tough one, dragnar. Not sure how you'd encourage destruction but also protect property. I wish you luck in finding a solution.
I just finished my weekly Minecrafting session with my mom. I finally got her to try mods. We just played for a couple hours on the Big Dig. It was so hard to stop playing. There's just... so much stuff...
At one point near the start I made a grand speech explaining to her all of the amazing things we can build in this modpack while she was bent over the crafting table making something, giving her our options and trying to get her to choose a goal for us to work towards.
Me: "There's combat mechs, power armor, magic teleportation books, pipes and machines, automatic farms, customized tools, and we can even build a rocket ship and go to the moon!"
Mom: "Right. ...How do I make a hoe?"
It figures, this was the one time I wasn't recording. I've been fighting with my video drivers (certain programs don't work with old drivers, so I install newer ones, and several more programs stop working...) and I managed to get RaidCall and Minecraft both working with one set of drivers, but OBS wouldn't start. : / Nevertheless, I spent several minutes gasping for breath with laughter.