Then keep your wireless signal to yourself.

Man arrested for using coffee shop's wireless signal.

A 20-year-old man in Vancouver, Wash., was charged with theft of services
for allegedly sitting in a coffee shop parking lot and using its wireless
Internet service for months, according to a report.

If you don't want people outside to use it, find a way to keep the signal from getting outside.

I liken this story to someone opening their windows and turning up their stereo, then arresting the neighbors for listening to the music.

[H/T 2 Buzzpage.]