My brother actually IS a copyright attorney, but I learned about the Cease & Desist letters elsewhere. The biggest factor in Topps' favor back in the 70s was that the series would be on the shelves for such a short time before they sold out that offended product manufacturers rarely had time to find out about the offending gag, contact their attorney, and get the legal notice mailed out before the gag was gone already. The letter would arrive at Topps, and they could sell any remaining stock on the shelves before suit was instituted. In today's suit-happy society, people are much quicker on the draw with attorneys, and many companies maintain "in house" counsel. Some manufactures are famous for how aggressively they protect their brand names. With deep pockets to fund expensive legal battles, it changed the equation significantly, and it makes more economic sense to avoid the manufactures who are known to "bite" hard. The actual cases decided on the issue of parody are very supportive of Topps, but that doesn't mean it wouldn't be expensive and time consuming to fight the issue in court. The profit margin on the cards isn't significant enough to make such fights worthwhile. I've never seen an actual Cease & Desist letter, but I can tell you that dozens of my ideas have been shot down simply for fear of annoying the wrong brand owner!
