Now suppose I came up to you at the supermarket and offered you the following bet:
"1-Methylcylopropene is a gas that helps apples last longer. Here's a brochure explaining it all. It makes apples better.* But I have a bet for you. I bet that sales of the labeled apples will be lower today than yesterday and that sales of the unlabeled apples will be higher today than they were yesterday. $10, even odds."Would you bet against me?
That's why I don't like mandatory labeling of GMO foods. A label saying "This product may contain ingredients derived from Genetically Modified Organisms" doesn't just tell people that there could be GMOs in the product. It also tells us that the government is sufficiently worried about GMOs that it thinks you should be told about it.
There's consequently a big difference between producers voluntarily labeling their products as GMO-free and the government mandating everyone label products that may contain GMOs.
Here's Mark Lynas from earlier this year. As best I can tell, the "consensus among people who know about this stuff" is as strong on GMOs as it is on climate change. Or at least I see a whole lot of people who know a whole lot about this stuff treating the GMO-worriers with about as much disdain as they treat the anti-vaccination, anti-fluoride, and "global warming doesn't exist" people. I consequently conclude that there's no scientific basis for deeming the risks of GMOs sufficiently worrying to get the hooples all riled up by mandating labels.
I also see nothing banning anybody from putting "GMO-Free" labels on their products for those who really do want to worry about that stuff. Even if their understanding of the science seems wrong, I see no reason that producers shouldn't cater to their fears. It seems very plausible that they get very real disutility from eating things that might have had GMOs in them, and that voluntary labeling of GMO-free products can make them better off. Just like people who dislike chemicals are made better off by the availability of an "Organic Food" section at the supermarket.
For an opposing view, see John Small.
* From Watkins (2006): "The rapidly ripening summer apple 'Anna' treated with 1-MCP that had less fruity, ripe and overall aromas, and were firmer, crisper, juicier and less mealy, were more preferred in sensory analysis than untreated fruit (Lurie et al, 2002; Pre-Aymard et al., 2005)."
Note however that I know basically nothing about this chemical; I just Googled for some food chemical that looked harmless.