Hi, HomeAgain. Yes, the magnets are glued in on the bottom and around the entire perimeter, and then more glue is applied to the top and the wooden disc is glued on top. As you might have seen in the FAQs section of the website, they have undergone physical and mechanical testing at an independent third-party lab pursuant to the CPSIA. In a non-scientific setting, I have tested them myself by banging them with a hammer, digging into them with a screwdriver, and throwing them against the floor and wall over and over again, and the magnets aren't affected whatsoever. Even using a screwdriver, the magnets are very difficult to get out. I would not want a dog to gnaw on them, however. Eventually, I suppose, the dog could crack a piece open and chew enough to dislodge the magnet from its housing. And you certainly don't want a human or animal to swallow a magnet - very, very dangerous, as the website warns repeatedly.
And, yes, we offer a 100% lifetime guarantee on all pieces. That's not really to guarantee the magnet spontaneously dislodging - I'm not particularly worried about that - it's more for if you step on a piece and accidentally break it. The wood, of course, will break if stepped on or bent too far, like any thin piece of wood. But in any case, I'll send you a new replacement piece for free.
Thanks for the questions and the interest.
Tom Scholl
Bracks Toys LLC
www.clickclackbracks.com