Crazy T-Shirts

So while looking at a site with a lot of cool, but expensive, products that make good gifts I came across a shirt that detects wi-fi. This is a very cool idea because you wouldn't need to drag your laptop out of its case and start it up and wait around for it to load only to find out that the McDonald's you are in doesn't have wi-fi, you could just look at your shirt! It would be ideal for travelers and kids on campus who don't know which buildings have wi-fi.

Realistically, if a company could come up with a small sticker that could go on the back of your watch or a keychain you could clip to your keys that would be easier for me to buy. I would be willing to spend $10 on a keychain that would tell me when wi-fi is around, that would be great! It could even be part of a jump drive, which would make it convenient since you would probably always have your jump drive around when you are looking for wi-fi.