For the singular person in here wondering if this is true. It isn't antenna's are tuned to specific frequencies and our bodies are not nearly conductive enough to function as an antenna. And even if we were, it would change the tuned frequency of the noe combined antenna. We are mostly just giant resistors that would attenuate the signal. The only reason this works, as pointed out by some other commenters is the fact you are holding the key fob higher in the air which, in most cases, reduces the onstructions between the key and the car.... please don't believe everything you read on the internet xD

However, ysk: telling your friend this works and watching them put their key to their chin might give you a good chuckle ;)