Yes; it’s one of the bullet points I raise at
Of course different wallets can have different defaults. For the reference Rust wallet, I expect the configuration file will have a mwixnet section where lists of mwixnet servers can be defined similar to how seed lists and peer lists are currently defined. But I would expect any hardcoded lists to be commented out, waiting for the user to choose one to uncomment before enabling mwixing. That way, the default behaviour is the simplest one and the user is not surprised by the change in behaviour if a set of selected mwixnet nodes interrupts or ceases operation for whatever reason.
If a particular mwixnet service proves to be both popular and reliable for a long period, and we expect the majority of Rust reference wallet users to make a particular configuration change, then it makes more sense to discuss change of this default.
Other wallet implementations may choose to enable mwixing by default.