dropping a townbell on a Pclaim is perfectly legit style of play. while i wont dismiss its kinda cheap to abuse the waste claim system to prevent v/p claim creation under the waste band (given the range of waste claims).. as for the walls in the guide, nothing in the guide said you had to build walls in tandem (aka side by side) it just said 3+ stone walls which could mean a 1000/1000 claim with 5 tile gap per wall would work just as well as a 5/5 claim area with walls back to back. though the guide should be updated with the new wall mechanics now as i dont believe it covers waste claims or wall splash currently.
as far as i can tell from the posted screen shots, the only abuse they may have used was an off claim wall bash to generate splash. which frankly i still think shouldnt take place or very least cause crimes of waste/vandalize so should activate blazers that are in-range of it. (though its easy to limit that sort of underhanded play by just expanding pclaim out 5-10 tiles in all 4 directions and keeping walls 5 tiles from edge.)