There simply aren't a lot of people who have used that product. For good reason. The correct method for tile installation utilizes thinset, not glue.

The worst that can happen is that removing the tile also removes the paper backing from the drywall. If that happens, that's handleable. You can either paint what remains with Gardz and skim with a setting compound, or if there aren't chunks missing, a second coat of Gardz and tile right on top of that. IF this is tile in a decorative spot and not a functional one, that is. If this is something like in a shower, you've got to remove everything and start over.