Oh yeah:

I'll post another hint every few days. If nobody wins in a reasonable amount of time, I may move the device to a better location or add an antenna.

Print out the first posting and keep it with you. It may help if someone asks what that geeky stuff in your car is.

I'd love to see more people set up challenges like this. If more appear in the area, I'll see if I can find yours before you find mine.

Could this be integrated with geocaching somehow? Maybe for the next challenge, the SSID indicates lat/long of a prize?