That sounds like an extreme form of the body-shielding technique, which does actually work (see posts in this thread and others). The technique sounds daft, but is based on perfectly sound Physics. Your body absorbs microwaves, including wifi signals. If you stand close to your router, your own signal will penetrate the body-shielding, but more distant signals will not. If you are lucky, that will exclude all n-type signals and allow you to connect to your own b/g.

In my apartment building there are at least 30 AP's within range of Nokia 770 and N800. Body-shielding reduces that to three, including my own. I can connect 100% of the time. If either of my two closest neighbours were to install an n router, I probably would not succeed any more with the 770.

Theoretically, any large piece of unfrozen meat should do just as well as your body. However, you are more likely to have your body available when you want to connect wifi. Clothing does not interfere with the process and is advised for avoiding smudges on your screen.

2.4 GHz portable phones also interfere with your wifi connection. They are even worse than n routers, in that they will break an existing connection. This is a problem for high-end laptops as well as for Nokia 770.