> Who is opting in to getting spammed?

Generally they're opting in to save money and get good deals at their favorite eating establishments. For some, getting this via text is a preferred method and less friction than downloading an app or alternative medium.

> I'm going to assume you're not using dark patterns to pull one over people while still claiming to be "opt-in"

these wouldn't hold up very well in a lawsuit even if you wanted to do this