First, let me make it clear that I know my memory on some of these issues is fuzzy around the edges.
Yes, RATINGS on radio got into some trouble maybe as far back as 1960 or so because stations were creating sham mechanisms so they could claim to be NUMBER ONE, and if they weren't brazen enough to claim Number One, they would quote the mechanism as having declared the station to have THE FASTEST GROWING AUDIENCE in the market. Says who? They never wanted to explain that. Finally the government said: If you are going to quote audience studies..... you WILL INCLUDE the dry, dusty documentation.
My favorite example of the 'crap' of that era was a station in Little Rock, AR claiming to be number one. It was the era when three staff members at just about any station could spend a long week-end creating a new play list, crafting some new promos and liners, and overnight, ON THE CHEAP, turn smaller metro markets upside down! Then a month later three staff members of the previously 'best station in town' when take a case of beer to some motel room and spend the week-end creating a new image and for the next three months, the market would again turn upside down. Here is the example of the 'crap'. The 'weak-sister' station that out of nowhere claimed to be number one had run a contest that you could win only by sending your answer to the question, your entry, via a Western Union Telegraph. (The listener could enter the contest for maybe a dollar or maybe a bit less.) Apparently Western Union would promote this idea because it meant revenue for them, and they would give the radio station a report on how many telegrams were received by each radio station in the market for the most recent time period. Not exactly what we today would refer to as "a scientifically accurate survey".
That kind of covers FCC and/or FTC mandated disclaimers... and my fuzzy memory is that ONLY contests involving listeners required disclaimers.
As time went on some years later the Federal Trade Commission and the Food and Drug Administration began dictating that certain advertising concepts, where presented via newspaper, radio, TV or magazines had to carry "fine print" which we in the world of broadcasting in particular call "disclaimers".
The tobacco industry was required to make disclosures about cancer possibilities. Tell me what year that happened?
The pharmaceutical industry was required to make disclosures about possible side effects of drugs and supplements. Tell me what year that happened?
And the one I mentioned: Both state and the Federal government got into the "truth in lending" issues and that resulted in radio ads by car dealers having disclosures.... but ONLY if they mentioned anything about financing the car. I know when that came about because I had to program on our computer the feature that would also put a disclaimer on the bank loan agreement or the GMAC loan agreement. I also tried to write a PC based program for used car dealers in Indiana who were in the "Buy Here Pay Here" weekly payday loan arrangements. (That went no where for me because some software company created a sweetheart deal with the state where THEIR program decided how the fractions would round up and round down that that because THE STATE REQUIREMENT.... other vendors need not apply. That was in the era of 1987, 1988 or something close to that.
Radio was slow to be impacted by some of these disclaimer schemes because at the retail level, many advertisers chose not to be pioneers and they just avoided talking about finance plans in their radio ads because they knew the public was not ready to deal with the flotsam.