"I think when making these decisions, we as developers have to consider what is best for the broadest number of users and be realistic about the type of users we have. If a user is already not updating plugins regularly, it is unlikely they are going to have the awareness to flip a toggle to turn auto-updates on. So opt-in makes them mostly useless."

It seems that, once again, where automatic updates are involved, developers forget Freedom 0:

"The freedom to run the program as you wish

The freedom to run the program means the freedom for any kind of person or organization to use it on any kind of computer system, for any kind of overall job and purpose, without being required to communicate about it with the developer or any other specific entity. In this freedom, it is the user's purpose that matters, not the developer's purpose; you as a user are free to run the program for your purposes, and if you distribute it to someone else, she is then free to run it for her purposes, but you are not entitled to impose your purposes on her."