Section 593d.
any person who, for the purpose of intercepting, receiving, or using any program or other service carried by a multichannel video or information services provider that the person is not authorized by that provider to receive or use, commits any of the following acts is guilty of a
public offense.

I think that you may be in the sticky gray area here. My guess is that the “service providers” service stops at the end of a wire entering the house, with a contract to provide a certain amount of bandwidth over that wire. The wireless access point likely belongs to the neighbor, and he can at his discression divy up his bandwidth with his own networking equipment any way he sees fit. Sharing with the neighbor would be no different legally than sharing with a family member/roommate. Steal access from Sprint or Verizon and the above would apply.