In Hap's case, while it was mildly irritating, he bent the rules because they allowed him to bend the rules. I really don't think he was trying to get away with anything, but Jim Lange kept giving him that opening.
Oddly, Jim would say that they were more lenient in the Golden Medley since it was against the house. Fine, if we are talking about minor words like "of" or "to", but giving extra time for a contestant to formulate an answer is not "against the house" but against the other players in the tournament and to those who missed the tournament. It's inconsistent, and not the contestant's fault. Not surprisingly, Sandy Frank is more strict when it involves a cash round, but not when a contestant adds a fabulous sponsored prize.
I don't think he took advantage of the talk-as-long-as-you-say-the-lyrics rule. It did get to some ridiculous levels for other contestants sometimes, but it is far better than the 2020s rules that eliminate you for saying one more word than the exact title. Or worse, if you don't say pass, you don't get prodded by the host to do so, you get the wet fart buzzer.