The good news is that some courts are beginning to agree.
The bad news is that the DMCA still makes it illegal for you to use third-party garage door openers. See page 63:
THE COURT: ... Isn't it a logical conclusions from your argument that your client's customers are all in violation of 1201(a)(1)? ...You decide! The RIAA and DirecTV people have certainly shown it can be done.
MR. FINK: I would say under the statutory language that's true.
THE COURT: Do you intend to bring an enforcement action against those customers?