I just built a small wall around some planting beds (12"tall) with a pavestone product from home depot. It was not my choice of products but the customer had their heart set on it, even though I gave them other options. The block only has a small lip on the back to keep it locked together. My question is, other than time and money would there be a major issue with gluing ever course to add strength to the wall? My thought is that it would no longer be a srw, but I was wondering what everyone else thought?