Like Twisted said when you set of TNT in your plot it can not go off before the owner of the plot has agreed to it with the command /Toggle tnt or /Plot set perm explosion on I believe but still if it is not on the explosion will still happen and this will take down pictures and all items that are 1 hit destroy, this can annoy people that got houses next to the player that did it cause their pictures pooped off (A TNT got a radius of 10 even tho it only destroy about 5 out when blowing up, so therefor it can simply destroy others stuff)