The tricky part is, the NFL IS entertainment. While the NFL wants to maintain the integrity of the sport, they have to balance the "watchability" of the product. If they called penalties on every play (because on judgement calls there probably could be a holding call on every play) it would be unbearable to sit through a game. The hard part is that, if you have players that routinely bend the rules, you just have to hope that if/when the refs get around to calling it, they don't do it on a "key" play. It's kind of playing with fire, but seems to have been working for the Chiefs and other teams over the years (Seattle's secondary during their SB years)