Many people will be surprised to hear that the answer is, "Yes." You can be charged with a crime under California law if you "steal" (some people prefer to say "borrow") a wireless internet signal from your neighbor or the local coffeehouse (even though arrests for this crime have been very rare).
Specifically, California's unauthorized computer access law, Penal Code 502 PC, considers unauthorized use of "computer services" to be a form of unauthorized computer access. "Computer services" includes wireless internet.
To violate this law, you need to have used the wi-fi without the owner's permission, and you need to have known that you were doing so without permission.
This raises the tricky question of how you would know that you didn't have the owner's permission. For example, if your neighbor did not protect his or her wireless signal with a password, it might be reasonable to assume that s/he was implicitly granting you permission to use it.
In most cases, this form of unauthorized access to computer services will be charged as a California misdemeanor, with a maximum county jail sentence of up to one (1) year and a maximum fine of five thousand dollars ($5,000).
But, incredibly enough, using wi-fi without permission in some cases can even lead to felony charges. This could be the case if:
- You have a prior conviction for this offense;
- Your unauthorized access caused some injury to the owner (including damage to his/her computer equipment) or caused him/her to spend more than five thousand dollars ($5,000); or
- The value of the computer services that you used was over nine hundred fifty dollars ($950).