I also have his Microchip # and information tag on my key chain.
I don't really want Jackson to be wearing it for reasons you stated. If someone were to find him, they would have his microchip number and I think it'd somehow be easier for them take ownership of him if they wanted to. Although, they would need a password (right?) to log into the website of the microchip company.... so I guess it still would be a challenge. But I just prefer to have it on me.
However... I wonder if it would be smarter for people to simply have the word "microchipped" on the dogs name tag, but with no number, so that if an honest person finds your dog, and brings it to a vet/shelter/etc, they will know to scan the dog.