Pretty informative edition for Tile Letter. In the back (NTCA Family Album) is Tom Hambrock (Hammy) and wife Jeanette. Looks like Hammy is trying to dance. It might just be a pose, though.
Also, the ad on page 65. Does that look like a Schluter drain in the Tile-redi shower floor? Wonder how they did that. Pretty tricky, eh?
Article page 52. While I agree the method used was atrocious, "spot bonding" did not cause the problem. The installation would have failed because of the primer (on slick tiles) no matter how the thin-set was applied. It appears also that the spots were not burned into the tiles, or the thin-set was stale or just plain inadequate.